Heme/coag/UA Flashcards
Insufficient centrifugation will result in:
A. A false increase in hematocrit (Hct) value
B. A false decrease in Hct value
C. No effect on Hct value
D. All of these options, depending on the patient
A Insufficient centrifugation does not pack down RBCs; therefore, the Hct, which is the
volume of packed cells, will increase.
Variation in red blood cell (RBC) size observed on the peripheral blood smear is
described as:
A. Anisocytosis
B. Hypochromia
C. Poikilocytosis
D. Pleocytosis
A A mature erythrocyte is approximately 7 to 8 μm in diameter. Variation in normal size
is denoted by the term anisocytosis. Hypochromia is a term that indicates increased
central pallor in erythrocytes, and poikilocytosis denotes variation in RBC shape
Which of the following is the preferred site for bone marrow aspiration and biopsy in an
adult?
A. Iliac crest
B. Sternum
C. Tibia
D. Spinous processes of a vertebra
A The iliac crest is the most frequently used site for bone marrow aspiration and biopsy.
This site is the safest and most easily accessible, with the bone being just beneath the
skin, and neither blood vessels nor nerves are in the vicinity
Mean cell volume (MCV) is calculated by using the following formula:
A. (Hgb ÷ RBC) × 10 where Hgb is hemoglobin in g/dL
B. (Hct ÷ RBC) × 10
C. (Hct ÷ Hgb) × 100
D. (Hgb ÷ RBC) × 100
B MCV is the average “volume” of the RBCs. This is obtained by dividing the Hct or
packed cell volume (PCV) by the RBC count in millions per microliter (μL) of blood
and multiplying by 10. MCV is expressed in cubic microns (μm3) or femtoliters (fL).
What term describes the change in shape of erythrocytes seen on a Wright-stained
peripheral blood smear?
A. Poikilocytosis
B. Anisocytosis
C. Hypochromia
D. Polychromasia
A Variation in the shape of erythrocytes on a peripheral blood smear is called
poikilocytosis. Anisocytosis refers to change in size. Hypochromia is increase in central
pallor in erythrocytes. Polychromasia describes the bluish tinge of the immature
erythrocytes (reticulocytes) circulating in peripheral blood
Calculate the mean cell hemoglobin concentration (MCHC) by using the following
values:
Hgb: 15 g/dL (150 g/L) Hct: 47 mL/dL (0.47)
RBC: 4.50 × 10^6/μL (4.50 × 10^12/L)
A. 9.5% (0.095)
B. 10.4% (0.104)
C. 31.9% (0.319)
D. 33.3% (0.333)
C MCHC is the average concentration of Hgb in RBCs expressed as a percentage. It
expresses the ratio of the weight of Hgb to the volume of erythrocytes and is calculated
by dividing Hgb by Hct and then multiplying by 100. A decrease in MCHC indicates
that cells are hypochromic. In this example, (15 ÷ 47) × 100 = 31.9%. The reference
range for MCHC is 32% to 36%.
A manual white blood cell (WBC) count was performed. In total 36 cells were counted in
all 9-mm2 squares of a Neubauer-ruled hemacytometer. A 1:10 dilution was used. What
is the WBC count?
A. 0.4 × 10^9/L
B. 2.5 × 10^9/L
C. 4.0 × 10^9/L
D. 8.0 × 10^9/L
A The formula used for calculating manual cell counts by using a hemacytometer is:
Number of cells counted × dilution factor × depth factor (10) ÷ area. In this example,
36 × 10 × 10 = 3600 ÷ 9 = 400/mm3 or 0.4 × 10^9/L.
When an erythrocyte containing iron granules is stained with Prussian blue, the cell is
called a:
A. Spherocyte
B. Leptocyte
C. Schistocyte
D. Siderocyte
D Siderocytes are RBCs containing iron granules and are visible when stained with
Prussian blue.
A 7.0-mL ethylenediaminetetraacetic acid (EDTA) tube is received in the laboratory
containing only 2.0 mL of blood. If the laboratory is using manual techniques, which of
the following tests will most likely be erroneous?
A. RBC count
B. Hgb
C. Hct
D. WBC count
C Excessive anticoagulant causes shrinkage of cells; thus, Hct will be affected. RBC and
WBC counts remain the same, as does the Hgb content.
A 1:200 dilution of a patient’s sample was made, and 336 RBCs were counted in an area
of 0.2 mm2. What is the RBC count?
A. 1.68 × 10^12/L
B. 3.36 × 10^12/L
C. 4.47 × 10^12/L
D. 6.66 × 10^12/L
B RBC count = number of cells counted × dilution factor × depth factor (10), ÷ area. In
this example, 336 × 200 × 10 = 672,000 ÷ 0.2 = 3.36 × 10^6/mm3 = 3.36 × 10^12/L.
What phagocytic cells produce lysozymes that are bacteriocidal?
A. Eosinophils
B. Lymphocytes
C. Platelets (PLTs)
D. Neutrophils
D Neutrophils are highly phagocytic and release lysozymes, peroxidase, and pyrogenic
proteins. Eosinophils migrate to sites where there is an allergic reaction or parasitic
infestation and release peroxidase, pyrogens, and other enzymes, including an oxidase
that neutralizes histamine. Eosinophils are poorly phagocytic and do not release
lysozyme.
If a patient has a reticulocyte count of 7% and Hct of 20%, what is the corrected
reticulocyte count?
A. 1.4%
B. 3.1%
C. 3.5%
D. 14%
B In anemic states, the reticulocyte percentage is not a true measure of reticulocyte
production. The following formula must be applied to calculate the corrected (for
anemia) reticulocyte count. Corrected reticulocyte count = reticulocytes (%) × (Hct ÷
45) where 45 is the average normal Hct. In this case, 7 × (20 ÷ 45) = 3.1.
A decreased osmotic fragility test would be associated with which of the following
conditions?
A. Sickle cell anemia
B. Hereditary spherocytosis (HS)
C. Hemolytic disease of the fetus and newborn
D. Acquired hemolytic anemia
A Osmotic fragility is decreased when numerous sickle cells and target cells are present
and is increased in the presence of spherocytes. Spherocytes are a prominent feature of
HS, hemolytic disease of the fetus and newborn, and acquired hemolytic anemia. The
osmotic fragility test reveals an increase in the presence of spherocytes, whereas a
decrease is seen when sickle cells, target cells, and other poikilocytes are present.
What effect would using a buffer at pH 6.0 have on a Wright-stained smear?
A. RBCs would be stained too pink
B. WBC cytoplasm would be stained too blue
C. RBCs would be stained too blue
D. RBCs would lyse on the slide
A The pH of the buffer is critical in Romanowsky staining. When the pH is too low (less
than 6.4), the RBCs take up more acid dye (eosin), becoming too pink. Leukocytes also
show poor nuclear detail when the pH is decreased
Which of the following erythrocyte inclusions can be visualized with supravital stain
but cannot be detected on a Wright-stained blood smear?
A. Basophilic stippling
B. Heinz bodies
C. Howell–Jolly bodies
D. Siderotic granules
B Heinz bodies are irregular, refractile, purple inclusions that are not visible with
Wright staining but show up with supravital staining. The other three inclusions can be
detected with Wright staining.
A falsely elevated Hct is obtained. Which of the following calculated values will not be
affected?
A. MCV
B. Mean corpuscular hemoglobin (MCH)
C. MCHC
D. Red blood cell distribution width (RDW)
B MCH = Hgb × 10/RBC count and is not affected by Hct. MCV = Hct × 10/RBC
count, and MCHC = Hgb × 100/Hct; therefore, an erroneous Hct will affect these
parameters. Centrifugal force for microhematocrit determination should be 12,000 g
for 5 minutes to avoid errors caused by trapped plasma. RDW is calculated by using
electronic cell counters and reflects the variance in the size of the RBC population.
Electronic cell counters calculate Hct from MCV and RBC count. Therefore, RDW
would be affected by an erroneous MCV.
A Miller disk is an ocular device used to facilitate counting of:
A. PLT
B. Reticulocytes
C. Sickle cells
D. Nucleated red blood cells (NRBCs)
B The manual reticulocyte count involves the counting of 1,000 RBCs. The Miller disk
is a reticle (grid) that is placed in the eyepiece of the microscope and divides the field
into two squares, one being nine times larger in size than the other. Reticulocytes are
enumerated in both the squares. Mature RBCs are counted in the smaller one.
SITUATION: RBC indices obtained on an anemic patient are as follows: MCV 88 μm3
(fL); MCH 30 pg; MCHC 34% (0.340). The RBCs on the peripheral blood smear would
appear:
A. Microcytic, hypochromic
B. Microcytic, normochromic
C. Normocytic, normochromic
D. Normocytic, hypochromic
C MCV, MCH, and MCHC are all within the reference interval (normal range); hence,
the erythrocytes should be of normal size and should reflect normal concentrations of
Hgb. Therefore, the anemia is normocytic normochromic
All of the following factors may influence the erythrocyte sedimentation rate (ESR)
except:
A. Blood drawn into a sodium citrate tube
B. Anisocytosis, poikilocytosis
C. Plasma proteins
D. Caliber of the tube
A EDTA and sodium citrate can be used without any effect on the ESR. Anisocytosis
and poikilocytosis may impede rouleaux formation, thus causing a low ESR. Plasma
proteins, especially fibrinogen and immunoglobulins, enhance rouleaux, increasing the
ESR. Reference ranges must be established for tubes of different calibers.
What staining method is used most frequently to stain and manually count
reticulocytes?
A. Immunofluorescence
B. Supravital staining
C. Romanowsky staining
D. Cytochemical staining
B The reticulum within reticulocytes consists of ribonucleic acid (RNA), which cannot
be stained with Wright stain. Supravital staining with new methylene blue is used to
identify reticulocytes.
The Coulter principle for counting of cells is based on the fact that:
A. Isotonic solutions conduct electricity better than cells do
B. Conductivity varies proportionally to the number of cells
C. Cells conduct electricity better than saline does
D. Isotonic solutions cannot conduct electricity
A Electronic cell (Coulter) counters use the principle of electrical impedance. Two
electrodes suspended in isotonic solutions are separated by a glass tube that has a small
aperture. A vacuum is applied, and as a cell passes through the aperture, it impedes the
flow of current and generates a voltage pulse.
A correction is necessary for WBC counts when NRBCs are seen on the peripheral
blood smear because:
A. The WBC count would be falsely lower
B. The RBC count is too low
C. NRBCs are counted as leukocytes
D. NRBCs are confused with giant PLTs
C Automated hematology analyzers enumerate all nucleated cells. NRBCs are counted
along with WBCs, falsely elevating the WBC count. To correct the WBC count, the
number of NRBCs per 100 WBCs should be determined. Corrected WBC count =
(uncorrected WBC count ÷ [NRBC’s + 100]) × 100.
Using an electronic cell counter analyzer, an increased RDW should correlate with:
A. Spherocytosis
B. Anisocytosis
C. Leukocytosis
D. Presence of NRBCs
B The RDW parameter correlates with the degree of anisocytosis seen on the
morphological examination. The reference range is 11.5% to 14.5%.
Given the following values, which set of RBC indices suggests spherocytosis?
A. MCV 76 μm3 MCH 19.9 pg MCHC 28.5%
B. MCV 90 μm3 MCH 30.5 pg MCHC 32.5%
C. MCV 80 μm3 MCH 36.5 pg MCHC 39.0%
D. MCV 81 μm3 MCH 29.0 pg MCHC 34.8%
C Spherocytes have decreased cell diameter and volume, and this results in loss of
central pallor and discoid shape. The index most affected is MCHC, usually being in
excess of 36%.
Which of the following statistical terms reflects the best index of precision when
comparing two complete blood count (CBC) parameters?
A. Mean
B. Median
C. Coefficient of variation
D. Standard deviation
C Standard deviation(s) describes the distribution of a sample of observations. It
depends on the dispersion of results and is most influenced by reproducibility or
precision. Because s is influenced by the mean, the coefficient of variation ([s ÷ mean]
× 100) can be used to compare precision of tests with different means
Which of the following is considered a normal Hgb?
A. Carboxyhemoglobin
B. Methemoglobin
C. Sulfhemoglobin
D. Deoxyhemoglobin
D Deoxyhemoglobin is the physiological Hgb that results from the unloading of O2 by
Hgb. This is accompanied by the widening of the space between β-chains and the
binding of 2,3-diphosphoglycerate (2,3-DPG) on a mole-for-mole basis
Which condition will shift the oxyhemoglobin dissociation curve to the right?
A. Acidosis
B. Alkalosis
C. Multiple blood transfusions
D. Increased quantities of Hgb S or C
A Acidosis is associated with a shift to the right of the oxyhemoglobin dissociation
curve and, therefore, increased O2 release (decreased affinity of Hgb for O2). Alkalosis
does the opposite. Multiple blood transfusions shift the curve to the left because
transfused blood is low in 2,3-DPG. Hgb S and Hgb C do not change the affinity of O2
for Hgb; however, many hemoglobinopathies do. For example, Hgb Kansas causes a
right shift, and Hgb Chesapeake causes a left shift of the oxyhemoglobin dissociation
curve.
What is the major type of leukocyte seen in the peripheral blood smear from a patient
with aplastic anemia?
A. Segmented neutrophil
B. Lymphocyte
C. Monocyte
D. Eosinophil
B In aplastic anemia, lymphocytes constitute the majority of the nucleated cells seen. In
aplastic anemia, bone marrow is spotty, with patches of normal cellularity. Absolute
granulocytopenia is usually present; however, lymphocyte production is less affected.
What is the normal WBC differential lymphocyte percentage (range) in the adult
population?
A. 5%–10%
B. 10%–20%
C. 20%–44%
D. 50%–70%
C The normal adult percentage of lymphocytes in a WBC differential is between 20%
and 44%, although normal ranges vary by institution, patient population, and testing
methodology. This range is higher in the pediatric population.
In which age group would 60% lymphocytes be a normal finding?
A. 6 months–2 years
B. 4–6 years
C. 11–15 years
D. 40–60 years
A There is relative neutropenia in children from ages 4 months to 4 years. Because of
this, the percentage of lymphocytes is increased in this population. This is commonly
referred to as a reversal in the normal differential percentage (or inverted differential)
Which of the following results on an automated differential suggests that a peripheral
blood smear should be reviewed manually?
A. Segs = 70%
B. Band = 6%
C. Mono = 15%
D. Eos = 2%
C A relative monocyte count of 15% is abnormal, given that the baseline monocyte
count in a normal differential is between 1% and 8%. An increased monocyte count
may signal a myeloproliferative process, such as chronic myelomonocytic leukemia, an
inflammatory response, or abnormal lymphocytes that may have been counted as
monocytes by an automated cell counter
Which is the first stage of erythrocytic maturation in which the cytoplasm is pink
because of the formation of Hgb?
A. Reticulocyte
B. Pronormoblast
C. Basophilic normoblast
D. Polychromatic normoblast
D In normal erythrocytic maturation, Hgb formation in the late polychromatic
normoblast stage gives the cytoplasm a prominent pink coloration. The RBC continues
to produce Hgb throughout the reticulocyte stage of development
Which of the following Hgb configurations is characteristic of Hgb H?
A. γ4
B. α2-γ2
C. β4
D. α2-β2
C The structure of Hgb H is β4. Hgb H disease is a severe clinical expression of α-
thalassemia in which only one α-gene out of four is functioning.
Which of the following can shift the Hgb oxygen (O2) dissociation curve to the right?
A. Increases in 2,3 DPG
B. Acidosis
C. Hypoxia
D. All of these options
D Increases in 2,3-DPG, acidosis, and hypoxia and rise in body temperature all shift the
Hgb O2 dissociation curve to the right. In anemia, although the number of RBCs is
reduced, the cells are more efficient at O2 delivery because there is an increase in RBC
2,3-DPG. This causes the oxyhemoglobin dissociation curve to shift to the right,
allowing more O2 to be released to tissues.
Autoagglutination of RBCs at room temperature can cause which of the following
abnormal test results?
A. Low RBC count
B. High MCV
C. Low Hct
D. All of these options
D Autoagglutination at room temperature may cause a low RBC count and high MCV
from an electronic counter. The Hct will be low because it is calculated from the RBC
count. Low RBC count and low Hct cause falsely high values of MCH and MCHC,
respectively.
Hypersplenism is characterized by:
A. Polycythemia
B. Pancytosis
C. Leukopenia
D. Myelodysplasia
C Hypersplenic conditions are generally described by the following four criteria: (1)
cytopenias of one or more peripheral cell lines, (2) splenomegaly, (3) bone marrow
hyperplasia, and (4) resolution of cytopenia by splenectomy.
Which of the following organs is responsible for the “pitting process” in RBCs?
A. Liver
B. Spleen
C. Kidney
D. Lymph nodes
B The spleen is the supreme filter of the body, pitting imperfections from the erythrocyte
without destroying the integrity of the membrane.
Spherocytes differ from normal RBCs in all of the following except:
A. Decreased surface to volume
B. No central pallor
C. Decreased resistance to hypotonic saline
D. Increased deformability
D Spherocytes lose their deformability because of a defect in spectrin, a membrane
protein, and are therefore prone to splenic sequestration and hemolysis
Which of the following is not associated with HS?
A. Increased osmotic fragility
B. MCHC greater than 36%
C. Intravascular hemolysis
D. Extravascular hemolysis
C Classic features of intravascular hemolysis, such as hemoglobinemia, hemoglobinuria,
or hemosiderinuria, do not occur in HS. The hemolysis seen in HS is an extravascular
process, rather than an intravascular process.
Which of the following disorders has an increase in osmotic fragility?
A. Iron deficiency anemia (IDA)
B. Hereditary elliptocytosis (HE)
C. Hereditary stomatocytosis
D. Hereditary spherocytosis (HS)
D Spherocytic cells have decreased tolerance to swelling and, therefore, hemolyse at a
higher concentration of sodium salt compared with normal RBCs.
The anemia seen in sickle cell disease is usually:
A. Microcytic, normochromic
B. Microcytic, hypochromic
C. Normocytic, normochromic
D. Normocytic, hypochromic
C. Sickle cell disease is a chronic hemolytic anemia classified as a normocytic,
normochromic anemia.
Which is the major Hgb found in the RBCs of patients with the sickle cell trait?
A. Hgb S
B. Hgb F
C. Hgb A2
D. Hgb A
D The major Hgb in sickle cell trait is Hgb A, which constitutes 50% to 70% of the total.
Hgb S comprises 20% to 40%, and Hgb A2 and Hgb F are present in normal amounts.
Select the amino acid substitution that is responsible for sickle cell anemia.
A. Lysine is substituted for glutamic acid at the sixth position of the α-chain
B. Valine is substituted for glutamic acid at the sixth position of the β-chain
C. Valine is substituted for glutamic acid at the sixth position of the α-chain
D. Glutamine is substituted for glutamic acid at the sixth position of the β-chain
B The structural mutation for Hgb S is the substitution of valine for glutamic acid at the
sixth position of the β-chain. Because glutamic acid is negatively charged, this
decreases its rate of migration toward the anode at pH 8.6.
All of the following are usually found in Hgb C disease except:
A. Hgb C crystals
B. Target cells
C. Lysine substituted for glutamic acid at the sixth position of the β–chain
D. Fast mobility of Hgb C at pH 8.6
D Substitution of a positively charged amino acid for a negatively charged amino acid in
Hgb C disease results in a slower electrophoretic mobility at pH 8.6.
Which of the following Hgbs migrates to the same position as Hgb A2 at pH 8.6?
A. Hgb H
B. Hgb F
C. Hgb C
D. Hgb S
C At pH 8.6, several Hgbs migrate together. These include Hgb A2, Hgb C, Hgb E, Hgb
0Arab, and Hgb CHarlem. These are located nearest the cathode at pH 8.6
Which of the following electrophoretic results is consistent with a diagnosis of the sickle
cell trait?
A. Hgb A: 40% Hgb S: 35% Hgb F: 5%
B. Hgb A: 60% Hgb S: 40% Hgb A2: 2%
C. Hgb A: 0% Hgb A2: 5% Hgb F: 95%
D. Hgb A: 80% Hgb S: 10% Hgb A2: 10%
B Electrophoresis at alkaline pH usually shows 50% to 70% Hgb A, 20% to 40% Hgb S,
and normal levels of Hgb A2 in a patient with the sickle cell trait.
In which of the following conditions will autosplenectomy most likely occur?
A. Thalassemia major
B. Hgb C disease
C. Hgb SC disease
D. Sickle cell disease
D Autosplenectomy occurs in sickle cell anemia as a result of repeated infarcts to the
spleen caused by an overwhelming sickling phenomenon
Which of the following is most true of paroxysmal nocturnal hemoglobinuria (PNH)?
A. It is a rare acquired stem cell disorder that results in hemolysis
B. It is inherited as a sex-linked trait
C. It is inherited as an autosomal dominant trait
D. It is inherited as an autosomal recessive trait
A PNH is a rare acquired stem cell disorder that results in abnormalities of the RBC
membrane. This causes the RBCs to become highly sensitive to complement-mediated
hemolysis. Because this is a stem cell disorder, abnormalities are seen in leukocytes
and PLTs, as well as in RBCs. PNH is characterized by recurrent, episodic
intravascular hemolysis, hemoglobinuria, and venous thrombosis.
Hemolytic uremic syndrome (HUS) is characterized by all of the following except:
A. Hemorrhage
B. Thrombocytopenia
C. Hemoglobinuria
D. Reticulocytopenia
D Hemolytic anemia of HUS is associated with reticulocytosis. The anemia seen in
HUS is multifactorial, with characteristic thrombocytopenia, schistocytes, and
polychromasia commensurate with the anemia.
The autohemolysis test result is positive in all of the following conditions except:
A. Glucose-6-phosphate dehydrogenase (G6PD) deficiency
B. HS
C. Pyruvate kinase (PK) deficiency
D. PNH
D The autohemolysis test result is positive in G6PD and PK deficiencies and in HS but
is normal in PNH because lysis in PNH requires sucrose to enhance complement
binding. The addition of glucose, sucrose, or adenosine triphosphate (ATP) corrects
autohemolysis of HS. Autohemolysis of PK can be corrected by ATP.
Which antibody is associated with paroxysmal cold hemoglobinuria (PCH)?
A. Anti-I
B. Anti-i
C. Anti-M
D. Anti-P
D PCH is caused by the anti-P antibody, a cold autoantibody that binds to the patient’s
RBCs at low temperatures and fixes complement. In the classic Donath–Landsteiner
test, hemolysis is demonstrated in a sample placed at 4°C then warmed to 37°C.
All of the following are associated with intravascular hemolysis except:
A. Methemoglobinemia
B. Hemoglobinuria
C. Hemoglobinemia
D. Decreased haptoglobin
A Methemoglobin occurs when iron is oxidized to the ferric state. Normally, iron is
predominantly in the ferrous state in the Hgb that circulates. During intravascular
hemolysis, the RBCs rupture, releasing Hgb directly into the bloodstream. Haptoglobin
is a protein that binds to free Hgb. The increased free Hgb in intravascular hemolysis
causes depletion of haptoglobin. As haptoglobin is depleted, unbound Hgb dimers
appear in the plasma (hemoglobinemia) and are filtered through the kidneys and
reabsorbed by the renal tubular cells. The renal tubular uptake capacity is
approximately 5 g/day of filtered Hgb. Beyond this level, free Hgb appears in urine
(hemoglobinuria). Hemoglobinuria is associated with hemoglobinemia
Autoimmune hemolytic anemia (AIHA) is best characterized by which of the following?
A. Increased levels of plasma C3
B. Spherocytic RBCs
C. Decreased osmotic fragility
D. Decreased unconjugated bilirubin
B Spherocytes are characteristic of AIHA and cause increased osmotic fragility. In
AIHAs, production of autoantibodies against one’s own RBCs causes hemolysis or
phagocytic destruction of RBCs. A positive direct antiglobulin (DAT or Coombs’) test
identifies in vivo antibody-coated and complement-coated RBCs. A positive DAT
result distinguishes AIHA from other types of hemolytic anemia that produce
spherocytes.
“Bite cells” are usually seen in patients with:
A. Rh null trait
B. Chronic granulomatous disease
C. G6PD deficiency
D. PK deficiency
C In patients with G6PD deficiency, the RBCs are unable to reduce nicotinamide
adenine dinucleotide phosphate (NADP); consequently, Hgb is denatured, and Heinz
bodies are formed. “Bite cells” appear in the peripheral circulation as a result of splenic
pitting of Heinz bodies.
The morphological classification of anemias is based on which of the following?
A. Myeloid:erythroid (M:E) ratio
B. Prussian blue stain
C. RBC indices
D. Reticulocyte count
C RBC indices classify the anemia morphologically. Anemias can be classified
morphologically by using laboratory data; physiologically, based on the mechanism;
and clinically, based on an assessment of symptoms
Which of the following is a common finding in aplastic anemia?
A. A monoclonal disorder
B. Tumor infiltration
C. Peripheral blood pancytopenia
D. Defective deoxyribonucleic acid (DNA) synthesis
C Aplastic anemia has many causes, such as chemical, drug, or radiation poisoning;
congenital aplasia; and Fanconi syndrome. All result in depletion of hematopoietic
precursors of all cell lines, leading to peripheral blood pancytopenia.
Congenital dyserythropoietic anemias (CDAs) are characterized by:
A. Bizarre multinucleated erythroblasts
B. Cytogenetic disorders
C. Megaloblastic erythropoiesis
D. An elevated M:E ratio
A There are four classifications of CDAs, each characterized by ineffective
erythropoiesis, increased unconjugated bilirubin, and bizarre multinucleated erythroid
precursors.
Microangiopathic hemolytic anemia is characterized by:
A. Target cells and Cabot rings
B. Toxic granulation and Döhle bodies
C. Pappenheimer bodies and basophilic stippling
D. Schistocytes and NRBCs
D Microangiopathic hemolytic anemia is a condition resulting from shear stress to the
erythrocytes. Fibrin strands are laid down within the microcirculation, and RBCs
become fragmented as they contact fibrin through the circulation process, forming
schistocytes.
Which antibiotic(s) is (are) most often implicated in the development of aplastic
anemia?
A. Sulfonamides
B. Penicillin
C. Tetracycline
D. Chloramphenicol
D Chloramphenicol is the drug most often implicated in acquired aplastic anemia.
About half the cases occur within 30 days after therapy, and about half are reversible.
Penicillin, tetracycline, and sulfonamides have been implicated in a small number of
cases.
Sickle cell disorders are:
A. Hereditary, intracorpuscular RBC defects
B. Hereditary, extracorpuscular RBC defects
C. Acquired, intracorpuscular RBC defects
D. Acquired, extracorpuscular RBC defects
A Sickle cell disorders are intracorpuscular RBC defects that are hereditary and result in
defective Hgbs being produced. The gene for sickle cell can be inherited either
homozygously or heterozygously.
Which of the following conditions may produce spherocytes in a peripheral blood
smear?
A. Pelger–Huët anomaly
B. Pernicious anemia
C. AIHA
D. Sideroblastic anemia
C Spherocytes are produced in AIHA. Spherocytes may be produced by one of three
mechanisms. First, they are a natural morphological phase of normal RBC senescence.
Second, they are produced when the cell surface:volume ratio is decreased, as seen in
HS. And, third, they may be produced as a result of antibody coating of RBCs. As the
antibody-coated RBCs travel through the spleen, the antibodies and portions of the
RBC membrane are removed by macrophages. The membrane repairs itself; hence, the
RBC’s morphology changes from a biconcave disk to a spherocyte.
A patient’s peripheral blood smear reveals numerous NRBCs, marked variation of
RBC morphology, and pronounced polychromasia. In addition to decreased Hgb and
decreased Hct values, what other CBC parameters may be anticipated?
A. Reduced PLTs
B. Increased MCHC
C. Increased MCV
D. Decreased RDW
C This patient’s abnormal peripheral blood smear indicates marked RBC regeneration,
causing many reticulocytes to be released from bone marrow. Because reticulocytes
are larger than mature RBCs, MCV will be slightly elevated.
What RBC inclusion may be seen in the peripheral blood smear from a patient
postsplenectomy?
A. Toxic granulation
B. Howell–Jolly bodies
C. Malarial parasites
D. Siderotic granules
B As a result of splenectomy, Howell–Jolly bodies may be seen in great numbers. One
of the main functions of the spleen is pitting, which allows inclusions to be removed
from the RBC without destroying the cell membrane.
Reticulocytosis usually indicates:
A. Response to inflammation
B. Neoplastic process
C. Aplastic anemia
D. RBC regeneration
D Reticulocytes are polychromatophilic macrocytes, and the presence of reticulocytes
indicates RBC regeneration. Bone marrow’s appropriate response to anemia is to
deliver RBCs prematurely to the peripheral circulation. In this way, reticulocytes and
possibly NRBCs may be seen in the peripheral blood smear.
Hereditary pyropoikilocytosis (HP) is an RBC membrane defect characterized by:
A. Increased pencil-shaped cells
B. Increased oval macrocytes
C. Misshapen budding fragmented cells
D. Bite cells
C HP is a membrane defect characterized by a spectrin abnormality and thermal
instability. MCV is decreased, and RBCs appear to be budding and fragmented.
The osmotic fragility test result in a patient with thalassemia major would most likely
show:
A. Increased hemolysis
B. Decreased hemolysis
C. Normal resistance to hemolysis
D. Decreased hemolysis after incubation at 37°C
B Osmotic fragility is decreased because numerous target cells are present and have
increased surface volume in patients with thalassemia major.
All of the following are characteristic findings in a patient with IDA except:
A. Microcytic, hypochromic RBC morphology
B. Decreased serum iron and ferritin levels
C. Decreased total iron-binding capacity (TIBC)
D. Increased RBC protoporphyrin
C In IDA, there is an increase in TIBC and in RBC protoporphyrin. Serum iron and
ferritin levels are decreased. IDA is characterized by a microcytic hypochromic
anemia.
IDA may be distinguished from anemia of chronic infection by:
A. Serum iron level
B. RBC morphology
C. RBC indices
D. TIBC
D In IDA, serum iron and ferritin levels are decreased, and TIBC and RBC
protoporphyrin are increased. In chronic disease, serum iron and TIBC are both
decreased because the iron is trapped in reticuloendothelial (RE) cells and is
unavailable to RBCs for Hgb production.
Which anemia has RBC morphology similar to that seen in IDA?
A. Sickle cell anemia
B. Thalassemia syndrome
C. Pernicious anemia
D. HS
B Thalassemia and IDA are both classified as microcytic, hypochromic anemias. IDA is
caused by defective heme synthesis, whereas thalassemia is caused by decreased
globin chain synthesis.
IDA is characterized by:
A. Decreased plasma iron, decreased % saturation, increased TIBC
B. Decreased plasma iron, decreased plasma ferritin, normal RBC porphyrin
C. Decreased plasma iron, decreased % saturation, decreased TIBC
D. Decreased plasma iron, increased % saturation, decreased TIBC
A IDA is characterized by decreased plasma iron, increased TIBC, decreased %
saturation, and microcytic, hypochromic anemia. Iron deficiency occurs in three
phases: iron depletion, iron-deficient erythropoiesis, and IDA
Storage iron is usually best determined by:
A. Serum transferrin levels
B. Hgb values
C. Myoglobin values
D. Serum ferritin levels
D Ferritin enters serum from all ferritin-producing tissues and, therefore, is considered a
good indicator of body storage iron. Because iron stores must be depleted before
anemia develops, low serum ferritin levels precede the fall in serum iron associated
with IDA.
All of the following are associated with sideroblastic anemia except:
A. Increased serum iron
B. Ringed sideroblasts
C. Hypochromic anemia
D. Decreased serum ferritin
D Sideroblastic anemias are a group of disorders characterized by hypochromic anemia,
ineffective erythropoiesis, an increase in serum and tissue iron, and the presence of
ringed sideroblasts in bone marrow
What is the basic hematological defect seen in patients with thalassemia major?
A. DNA synthetic defect
B. Hgb structure
C. β-chain synthesis
D. Hgb phosphorylation
C In thalassemia major, there is little or no production of the β-chain, resulting in
severely depressed or no synthesis of Hgb A. Severe anemia is seen, along with
skeletal abnormalities and marked splenomegaly. The patient is usually supported with
transfusion therapy.
Which of the following is the primary Hgb in patients with thalassemia major?
A. Hgb D
B. Hgb A
C. Hgb C
D. Hgb F
D Patients with thalassemia major are unable to synthesize the β-chain; hence, little or no
Hgb A is produced. However, γ-chains continue to be synthesized and lead to variable
elevations of Hgb F in these patients.
A patient has an Hct of 30%, an Hgb of 8 g/dL, and a RBC count of 4.0 × 10^12/L. What
is the morphological classification of this anemia?
A. Normocytic, normochromic
B. Macrocytic, hypochromic
C. Microcytic, hypochromic
D. Normocytic, hyperchromic
C The indices will provide a morphological classification of this anemia. MCV is 75 fL
(reference range 80–100 fL), MCH is 20 pg (reference range 27–31 pg), and MCHC is
26.6% (reference range 32%–36%). Therefore, the anemia is microcytic hypochromic.
In which of the following conditions is Hgb A2 elevated?
A. Hgb H
B. Hgb SC disease
C. β-thalassemia minor
D. Hgb S trait
C Hgb A2 is part of the normal complement of adult Hgb. This Hgb is elevated in β-
thalassemia minor because the individual with this condition has only one normal β-
gene; consequently, there is a slight elevation of Hgb A2 and Hgb F.
Which of the following parameters may be similar for the anemia of inflammation and
IDA?
A. Normocytic indices
B. Decreased serum iron concentration
C. Ringed sideroblasts
D. Pappenheimer bodies
B Thirty to fifty percent of the individuals with anemia of chronic inflammation
demonstrate a microcytic hypochromic blood picture, with decrease in serum iron.
Serum iron is decreased because it is unable to escape from the RE cells to be
delivered to the NRBCs in bone marrow.
Which morphological classification is characteristic of megaloblastic anemia?
A. Normocytic, normochromic
B. Microcytic, normochromic
C. Macrocytic, hypochromic
D. Macrocytic, normochromic
D Megaloblastic anemia is macrocytic normochromic because there is no defect in Hgb
synthesis. These anemias comprise a group of asynchronized anemias characterized by
defective nuclear maturation resulting from defective DNA synthesis. This abnormality
accounts for the megaloblastic features in bone marrow and macrocytosis in peripheral
blood
Which anemia is characterized by lack of intrinsic factor that prevents B12 absorption?
A. Tropical sprue
B. Transcobalamin deficiency
C. Blind loop syndrome
D. Pernicious anemia
D Pernicious anemia is caused by lack of intrinsic factor, which prevents vitamin B12
absorption
All of the following are characteristics of megaloblastic anemia except:
A. Pancytopenia
B. Elevated reticulocyte count
C. Hypersegmented neutrophils
D. Macrocytic erythrocyte indices
B Megaloblastic anemias are associated with ineffective erythropoiesis and, therefore, a
decrease in the reticulocyte count
A patient with a vitamin B12 anemia is prescribed a high dosage of folate. Which of the
following is expected as a result of this treatment?
A. An improvement in neurological problems
B. An improvement in hematological abnormalities
C. No expected improvement
D. Toxicity of the liver and kidneys
B Administration of folic acid to a patient with vitamin B12 deficiency will correct the
hematological abnormalities, but the neurological problems will persist. This helps
confirm the correct diagnosis of vitamin B12 deficiency.
Which of the following disorders is associated with ineffective erythropoiesis?
A. G6PD deficiency
B. Liver disease
C. Hgb C disease
D. Megaloblastic anemia
D Ineffective erythropoiesis is caused by destruction of erythroid precursor cells prior to
their release from bone marrow. Pernicious anemia results from defective DNA
synthesis; it is suggested that the asynchronous development of RBCs renders them
more prone to intramedullary destruction.
A 50-year-old patient is suffering from pernicious anemia. Which of the following
laboratory data are most likely for this patient?
A. RBC = 2.5 × 10^12/L; WBC = 12,500/μL (12.5 × 10^9/L); PLT = 250,000/μL (250 × 10^9/L)
B. RBC = 4.5 × 10^12/L; WBC = 6,500/μL (6.5 × 10^9/L); PLT = 150,000/μL (150 × 10^9/L)
C. RBC = 3.0 × 10^12/L; WBC = 5,000/μL (5.0 × 10^9/L); PLT = 750,000/μL (750 × 10^9/L)
D. RBC = 2.5 × 10^12/L; WBC = 2,500/μL (2.5 × 10^9/L); PLT = 50,000/μL (50 × 10^9/L)
D Patients with pernicious anemia demonstrate pancytopenia with low WBC, PLT, and
RBC counts. Because this is a megaloblastic process and a DNA maturation defect, all
cell lines are affected. In bone marrow, this results in abnormally large precursor cells,
maturation asynchrony, hyperplasia of all cell lines, and a low M:E ratio.
Which of the following may be seen in the peripheral blood smear from a patient with
obstructive liver disease?
A. Schistocytes
B. Macrocytes
C. Howell–Jolly bodies
D. Microcytes
B Patients with obstructive liver disease may have macrocytes on their peripheral blood
smear because of an increased tendency toward deposition of lipid on the surface of
RBCs. Consequently, the RBCs are larger or more macrocytic than normal RBCs.
The macrocytes typically seen in megaloblastic processes are:
A. Crescent shaped
B. Teardrop shaped
C. Oval shaped
D. Pencil shaped
C Macrocytes in true megaloblastic conditions are oval, as opposed to the round shape of
macrocytes usually seen in alcoholism and obstructive liver disease.
Which of the following are most characteristic of the RBC indices associated with
megaloblastic anemias?
A. MCV 99 fL, MCH 28 pg, MCHC 31%
B. MCV 62 fL, MCH 27 pg, MCHC 30%
C. MCV 125 fL, MCH 36 pg, MCHC 34%
D. MCV 78 fL, MCH 23 pg, MCHC 30%
C The RBC indices in a patient with megaloblastic anemia are macrocytic and
normochromic. The macrocytosis is prominent, with MCV ranging from 100 to 130
fL.
A patient has 80 NRBCs per 100 leukocytes. In addition to increased polychromasia on
the peripheral blood smear, what other finding may be present on the CBC?
A. Increased PLTs
B. Increased MCV
C. Increased Hct
D. Increased RBC count
B The patient will have increased MCV. One of the causes of a macrocytic anemia that
is not megaloblastic is increased reticulocyte count, here noted as increased
polychromasia. Reticulocytes are polychromatic macrocytes; therefore, MCV is
slightly increased.
Which of the following is an unusual complication that may occur in infectious
mononucleosis?
A. Splenic infarctions
B. Dactylitis
C. Hemolytic anemia
D. Giant PLTs
C Occasionally patients with infectious mononucleosis develop a potent cold agglutinin
with anti-I specificity. This cold autoantibody can cause strong hemolysis and
hemolytic anemia
In a patient with HIV infection, one should expect to see:
A. Shift to the left in WBCs
B. Target cells
C. Reactive lymphocytes
D. Pelgeroid cells
C HIV infection brings about several hematological abnormalities seen on peripheral
blood smear examination; most patients demonstrate reactive lymphocytes and have
granulocytopenia.
Which inclusions may be seen in leukocytes?
A. Döhle bodies
B. Basophilic stippling
C. Malarial parasites
D. Howell–Jolly bodies
A Döhle bodies are RNA-rich areas within polymorphonuclear neutrophils (PMNs) that
are oval and light blue. Although often associated with infectious states, they are seen
in a wide range of conditions and toxic reactions, including hemolytic and pernicious
anemias, chronic granulocytic leukemia, and therapy with antineoplastic drugs. The
other inclusions are associated with erythrocytes.
Which of the following is contained in the primary granules of the neutrophil?
A. Lactoferrin
B. Myeloperoxidase
C. Histamine
D. Alkaline phosphatase
B Myeloperoxidase, lysozyme, and acid phosphatase are enzymes that are contained in
the primary granules of neutrophils. The contents of secondary and tertiary granules
include lactoferrin, collagenase, NADPH oxidase, and alkaline phosphatase.
What is the typical reference range for relative lymphocyte percentage in the peripheral
blood smear from a 1-year-old child?
A. 1%–6%
B. 27%–33%
C. 35%–58%
D. 50%–70%
D The mean relative lymphocyte percentage for a 1-year-old child is 61% compared with
the mean lymphocyte percentage of 35% in an adult.
Qualitative and quantitative neutrophil changes noted in response to infection include
all of the following except:
A. Neutrophilia
B. Pelgeroid hyposegmentation
C. Toxic granulation
D. Vacuolization
B Neutrophil changes associated with infection may include neutrophilia, shift to the left,
toxic granulation, Döhle bodies, and vacuolization. Pelgeroid hyposegmentation is
noted in neutrophils from individuals with congenital Pelger–Huët anomaly and those
with an acquired anomaly induced by drug ingestion or secondary to certain
conditions, such as leukemia.
Neutropenia is present in patients with which absolute neutrophil count?
A. Less than 1.5 × 10^9/L
B. Less than 5.0 × 10^9/L
C. Less than 10.0 × 10^9/L
D. Less than 15.0 × 10^9/L
A Neutropenia is defined as an absolute decrease in the number of circulating
neutrophils. This condition is present in patients having neutrophil counts of less than
1.5 × 10^9/L.
The morphological characteristic(s) associated with Chédiak–Higashi syndrome is (are):
A. Pale blue cytoplasmic inclusions
B. Giant lysosomal granules
C. Small, dark-staining granules and condensed nuclei
D. Nuclear hyposegmentation
B Chédiak–Higashi syndrome is a disorder of neutrophil phagocytic dysfunction caused
by depressed chemotaxis and delayed degranulation. The degranulation disturbance is
attributed to interference from the giant lysosomal granules characteristic of this
disorder.
The familial condition of Pelger–Huët anomaly is important to recognize because this
disorder must be differentiated from:
A. Infectious mononucleosis
B. May–Hegglin anomaly
C. A shift-to-the-left increase in immature granulocytes
D. G6PD deficiency
C Pelger–Huët anomaly is a benign familial condition reported in 1 out of 6,000
individuals. Care must be taken to differentiate Pelger–Huët cells from the numerous
band neutrophils and metamyelocytes that may be observed during severe infection or
a shift-to-the-left of immaturity in granulocyte stages
SITUATION: A differential shows reactive lymphocytes, and the physician suspects
that a viral infection is the cause. What is the expected laboratory finding in a patient
with a cytomegalovirus (CMV) infection?
A. Heterophile antibody: positive
B. Epstein–Barr virus (EBV)–immunoglobulin M (IgM): positive
C. Direct antiglobulin test (DAT): positive
D. CMV–IgM: positive
D If both the heterophile antibody test and the EBV-IgM tests yield negative results in a
patient with reactive lymphocytosis and a suspected viral infection, serum should be
analyzed for IgM antibodies to CMV. CMV belongs to the herpes virus family and is
endemic worldwide. CMV infection is the most common cause of heterophile-negative
infectious mononucleosis
Neutrophil phagocytosis and particle ingestion are associated with an increase in O2
utilization called respiratory burst. What are the two most important products of this
biochemical reaction?
A. Hydrogen peroxide (H2O2) and superoxide anion (O2–)
B. Lactoferrin and NADPH oxidase
C. Cytochrome b and collagenase
D. Alkaline phosphatase and ascorbic acid
A The biochemical products of the respiratory burst involved in neutrophil particle
ingestion during phagocytosis are H2O2 and O2–. The activated neutrophil discharges
the enzyme NADPH oxidase into the phagolysosome, where it converts O2 to O2–,
which is then reduced to H2O2.
Which of the morphological findings are characteristic of reactive lymphocytes?
A. High nuclear:cytoplasmic (N:C) ratio
B. Prominent nucleoli
C. Basophilic cytoplasm
D. All of these options
D Both reactive lymphocytes and blasts may have basophilic cytoplasm, a high N:C
ratio, and the presence of prominent nucleoli. Blasts, however, have an extremely fine
nuclear chromatin staining pattern as viewed on a Wright– and Giemsa–stained smear.
Auer rods may be seen in all of the following except:
A. Acute myelomonocytic leukemia (M4)
B. Acute lymphoblastic leukemia (ALL)
C. Acute myeloid leukemia without maturation (AML:M1)
D. Acute promyelocytic leukemia (PML; M3)
B Auer rods are not seen characteristically in lymphoblasts. They may be seen in
myeloblasts, promyelocytes, and monoblasts
Which type of anemia is usually present in a patient with acute leukemia?
A. Microcytic, hyperchromic
B. Microcytic, hypochromic
C. Normocytic, normochromic
D. Macrocytic, normochromic
C Acute leukemia is usually associated with a normocytic normochromic anemia.
Anemia in acute leukemia is usually present from the onset and may be severe;
however, there is no inherent nutritional deficiency leading to a microcytic,
hypochromic, or megaloblastic process.
In leukemia, which term describes the peripheral blood finding of leukocytosis with a
shift to the left, accompanied by NRBCs?
A. Myelophthisis
B. Dysplasia
C. Leukoerythroblastosis
D. Megaloblastosis
C The presence of immature leukocytes and NRBCs is called leukoerythroblastosis and
frequently denotes a malignant or myeloproliferative process. Myelophthisis refers to
replacement of bone marrow by a disease process, such as a neoplasm. The
development of abnormal tissue is called dysplasia.
The basic pathophysiological mechanisms responsible for producing signs and
symptoms in leukemia include all of the following except:
A. Replacement of normal marrow precursors by leukemic cells causing anemia
B. Decrease in functional leukocytes causing infection
C. Hemorrhage secondary to thrombocytopenia
D. Decreased erythropoietin production
D A normal physiological response to anemia would be an increase in the kidney’s
production of erythropoietin. The accumulation of leukemic cells in bone marrow leads
to marrow failure, which manifests as anemia, thrombocytopenia, and
granulocytopenia.
Which type of acute myeloid leukemia is called the true monocytic leukemia and follows
an acute or subacute course characterized by monoblasts, promonocytes, and
monocytes?
A. Acute myeloid leukemia, minimally differentiated
B. Acute myeloid leukemia, without maturation
C. Acute myelomonocytic leukemia
D. Acute monocytic leukemia
D Acute monocytic leukemia has an incidence of 1% to 8% of all acute leukemias. It has
a distinctive clinical manifestation of monocytic involvement, resulting in skin and
gum hyperplasia. The WBC count is markedly elevated, and prognosis is poor
In which age group does ALL occur with the highest frequency?
A. 1–15 years
B. 20–35 years
C. 45–60 years
D. 60–75 years
A ALL usually affects children from ages 1 to 15 years and is the most common type of
acute leukemia in this age group. In addition, ALL constitutes the single most
prevalent malignancy in pediatric patients.
Disseminated intravascular coagulation (DIC) is most often associated with which of the
following types of acute leukemia?
A. Acute myeloid leukemia, without maturation
B. Acute promyelocytic leukemia (PML)
C. Acute myelomonocytic leukemia
D. Acute monocytic leukemia
B In patients with acute PML, the azurophilic granules in the leukemic promyelocytes
contain thromboplastic substances. When released from promyelocytes, these activate
soluble coagulation factors causing DIC
An M:E ratio of 10:1 is most often seen in:
A. Thalassemia
B. Leukemia
C. Polycythemia vera (PV)
D. Myelofibrosis
B A disproportionate increase in the myeloid component of bone marrow is usually the
result of a leukemic state. The normal M:E ratio is approximately 4:1 in adults with
normal cellularity.
Which of the following is a characteristic of Auer rods?
A. They are composed of azurophilic granules
B. They stain positive on periodic acid–Schiff (PAS) staining
C. They are predominantly seen in chronic myelogenous leukemia (CML)
D. They are nonspecific esterase positive
A Auer rods are a linear projection of primary azurophilic granules and are present in the
cytoplasm of myeloblasts and monoblasts in patients with acute leukemia.
SITUATION: The following laboratory values are seen:
WBC = 6.0 × 109/L Hgb = 6.0 g/dL
RBC = 1.90 × 1012/L Hct = 18.5%
PLT = 130 × 109/L
Serum vitamin B12 and folic acid: normal
WBC Differential Bone Marrow
6% PMNs 40% myeloblasts
40% lymphocytes 60% promegaloblasts
4% monocytes 40 megaloblastoid
NRBCs/100 WBCs
50% blasts
These results are most characteristic of:
A. Pernicious anemia
B. Acute myeloid leukemia, without maturation
C. Acute erythroid leukemia
D. Acute myelomonocytic leukemia
C In acute erythroid leukemia, greater than 50% of nucleated bone marrow cells are
erythroid and greater than 30% nonerythroid cells are blasts. Pernicious anemia results
in pancytopenia and low vitamin B12 concentrations.
A 24-year-old man with Down syndrome presents with fever, pallor, lymphadenopathy,
and hepatosplenomegaly. His CBC results are as follows:
WBC = 10.8 × 109/L RBC = 1.56 × 1012/L
8% PMNs Hgb = 3.3 g/dL
25% lymphocytes Hct = 11%
67% PAS-positive blasts PLT = 2.5 × 109/L
These findings are suggestive of:
A. Hodgkin lymphoma
B. Myeloproliferative disorder
C. Leukemoid reaction
D. Acute lymphocytic leukemia
D Common signs of ALL are hepatosplenomegaly (65%), lymphadenopathy (50%), and
fever (60%). Anemia and thrombocytopenia are usually present, and the WBC count is
variable. The numerous lymphoblasts are generally PAS positive.
SITUATION: A peripheral blood smear shows 75% blasts. These stain positive for both
Sudan Black B (SBB) and peroxidase. Given these values, which of the following
disorders is most likely?
A. Acute myelocytic leukemia (AML)
B. CML
C. Acute undifferentiated leukemia (AUL)
D. ALL
A AML blasts stain positive for SBB and peroxidase. Usually, less than 10% blasts are
found in peripheral blood smears from patients with CML, unless there has been a
transition to blast crisis. The organelles in the cells of AUL are not mature enough to
stain positive for SBB or peroxidase. Blasts in ALL are characteristically negative with
these stains
In myeloid cells, the stain that selectively identifies phospholipid in the membranes of
both primary and secondary granules is:
A. PAS
B. Myeloperoxidase
C. SBB
D. Terminal deoxynucleotidyl transferase (TdT)
C Phospholipids, neutral fats, and sterols are stained by SBB. The PAS reaction stains
intracellular glycogen. Myeloperoxidase is an enzyme present in the primary granules
of myeloid cells and, to a lesser degree, in monocytic cells. TdT is a DNA polymerase
found in thymus-derived lymphocytes and some bone marrow–derived lymphocytes.
Sodium fluoride may be added to the naphthyl ASD acetate (NASDA) esterase reaction.
The fluoride is added to inhibit a positive reaction with:
A. Megakaryocytes
B. Monocytes
C. Erythrocytes
D. Granulocytes
B NASDA stains monocytes (and monoblasts) and granulocytes (and myeloblasts). The
addition of fluoride renders monocytic cells (and blasts) negative, thus allowing for
differentiation from granulocytic cells, which remain positive.
Leukemic lymphoblasts reacting with anti–common acute lymphoblastic leukemia
antigen (anti-CALLA) are characteristically seen in:
A. B-cell ALL
B. T-cell ALL
C. Null-cell ALL
D. Common ALL
D The majority of non-T, non-B ALL blast cells display the CALLA marker.
Lymphoblasts of common ALL are TdT positive and CALLA positive but do not have
surface membrane IgM or μ-chains and are pre-B lymphoblasts. Common ALL has a
lower relapse rate and better prognosis compared with other immunologic subtypes of
B-cell ALL.
Which of the following reactions are often positive in ALL but are negative in AML?
A. TdT and PAS
B. Chloroacetate esterase and nonspecific esterase
C. SBB and peroxidase
D. New methylene blue and acid phosphatase
A PAS is positive in about 50% of ALL with L1 and L2 morphology but is negative in
ALL with L3 morphology (B-cell ALL). TdT is positive in all types of ALL except L3.
Both TdT and PAS are negative in AML
A patient’s peripheral blood smear and bone marrow both show 70% blasts. These cells
are negative on SBB staining. Given these data, which of the following is the most likely
diagnosis?
A. AML
B. Chronic lymphocytic leukemia (CLL)
C. Acute PML
D. ALL
D SBB stains phospholipids and other neutral fats. It is the most sensitive stain for
granulocytic precursors. Lymphoid cells rarely stain positive with SBB. Because 70%
lymphoblasts would never be seen in CLL, the correct response is ALL.
Which of the following leukemias are included in the 2008 World Health Organization
classification of myeloproliferative neoplasms (MPN)?
A. CML
B. Chronic neutrophilic leukemia (CNL)
C. Chronic eosinophilic leukemia (CEL)
D. All of these options are classified as MPN
D The WHO classification system includes the following disorders under MPN: CML,
CNL, CEL, essential thrombocythemia (ET), PV, primary (idiopathic) myelofibrosis,
hypereosinophilic syndrome, mast cell disease, and MPNs unclassified
In addition to morphology, cytochemistry, and immunophenotyping, the WHO
classification of myelo- and lymphoproliferative disorders is based on which
characteristic?
A. Proteomics
B. Cytogenetic abnormalities
C. Carbohydrate-associated tumor antigen production
D. Cell signaling and adhesion markers
B In addition to morphology, cytochemical stains, and flow cytometry, the WHO
classification relies heavily on chromosomal and molecular abnormalities.
The WHO classification requires what percentage for the blast count in blood or bone
marrow for the diagnosis of AML?
A. At least 30%
B. At least 20%
C. At least 10%
D. Any percentage
B The WHO classification of AML requires that 20% or greater of nucleated bone
marrow cells be blasts, whereas the French–American-British (FAB) classification
generally requires 30% or greater. The WHO classifies AML into five subgroups:
acute myeloid leukemias with recurrent genetic disorders; acute myeloid leukemia with
multilineage dysplasia; acute myeloid leukemia and myelodysplastic syndromes,
therapy related; acute myeloid leukemia (not otherwise categorized); and acute
leukemia of ambiguous lineage.
What would be the most likely designation by the WHO for AML M2 by the FAB
classification?
A. AML with t(15;17)
B. AML with mixed lineage
C. AML with t(8;21)
D. AML with inv(16)
C AML with t(8;21) is classified under the category “AML with Recurrent Genetic
Abnormalities” by the WHO. This translocation occurs in up to 15% of cases of AML
and may be the most common translocation. The AML1–ETO translocation occurs
chiefly in younger patients and often in cases of acute myeloblastic leukemia with
maturation, FAB M2. The translocation involves the fusion of the AML1 gene on
chromosome 21 with the ETO gene on chromosome 8.
What would be the most likely designation by the WHO for AML M3 by the FAB
classification?
A. AML with t(15;17)
B. AML with mixed lineage
C. AML with t(8;21)
D. AML with inv(16)
A AML with t(15;17) is classified under the category “AML with Recurrent Genetic
Abnormalities” by the WHO. Acute PML (known as M3 under the FAB system) is
composed of abnormal promyelocytes with heavy granulation, sometimes obscuring
the nucleus, and abundant cytoplasm. Acute PML contains a translocation that results
in the fusion of a transcription factor called PML on chromosome 15 with the alpha
(α)-retinoic acid receptor gene (RARα) on chromosome 17.
Which AML cytogenetic abnormality is associated with AML M4 with marrow
eosinophilia under the WHO classification of AML with recurrent genetic
abnormalities?
A. AML with t(15;17)
B. AML with mixed lineage
C. AML with t(8;21)
D. AML with inv(16)
D AML with inv(16) has pericentric inversion of chromosome 16 and is associated with
M4 with marrow eosinophilia, M4eo under the FAB system. The inv(16) results in the
fusion of the CBFβ gene on 16q22 with the MYH11 gene on 16p13.
What would be the most likely classification by the WHO for AML M7 by the FAB
classification?
A. Acute myeloid leukemias with recurrent genetic abnormalities
B. Acute myeloid leukemia with multilineage dysplasia
C. Acute megakaryoblastic leukemia classified under AML (not otherwise categorized)
D. Acute leukemias of ambiguous lineage
C Acute megakaryoblastic leukemia, which is equivalent to FAB M7, is a relatively
uncommon form of leukemia characterized by neoplastic proliferation of
megakaryoblasts and atypical megakaryocytes. Recognition of this entity was aided by
the use of platelet peroxidase (PPO) ultrastructural studies. PPO is distinct from
myeloperoxidase and is specific for the megakaryocytic cell line. Acute
megakaryoblastic leukemia is defined as an acute leukemia in which 50% or greater of
the blasts are of megakaryocytic lineage. In the WHO 2016 revision, it is classified
under “AML (not otherwise categorized).”
Repeated phlebotomy in patients with PV may lead to the development of:
A. Folic acid deficiency
B. Sideroblastic anemia
C. IDA
D. Hemolytic anemia
C The most common treatment modality utilized in PV is phlebotomy. Reduction of
blood volume (usually 1 unit of whole blood—450 cc) can be performed weekly or
even twice weekly in younger patients to control symptoms. The Hct target range is
less than 45% for men and less than 42% for women. IDA is a predictable
complication of therapeutic phlebotomy because approximately 250 mg of iron is
removed with each unit of blood.
In ET, the PLTs are:
A. Increased in number and functionally abnormal
B. Normal in number and functionally abnormal
C. Decreased in number and functional
D. Decreased in number and functionally abnormal
A In ET, the PLT count is extremely elevated. These PLTs are abnormal in function,
leading to both bleeding and thrombotic diathesis
Which of the following cells is considered pathognomonic for Hodgkin disease?
A. Niemann–Pick cells
B. Reactive lymphocytes
C. Flame cells
D. Reed–Sternberg (RS) cells
D The morphological common denominator in Hodgkin lymphoma is the RS cell. It is a
large, binucleated cell with a dense nucleolus surrounded by clear space. These
characteristics give the RS cell an “owl’s eye” appearance. Niemann–Pick cells (foam
cells) are histiocytes containing phagocytized sphingolipids that stain pale blue and
impart a foamlike texture to the cytoplasm. Flame cells are plasma cells with a
distinctive red cytoplasm. They are sometimes seen in the bone marrow of patients
with multiple myeloma.
In myelofibrosis, the characteristic abnormal RBC morphology is that of:
A. Target cells
B. Schistocytes
C. Teardrop-shaped cells
D. Ovalocytes
C The marked amount of fibrosis, both medullary and extramedullary, accounts for the
irreversible change in RBC morphology to a teardrop shape. The RBCs are “teared” as
they attempt to pass through the fibrotic tissue.
PV is characterized by:
A. Increased plasma volume
B. Pancytopenia
C. Decreased O2 saturation
D. Absolute increase in total RBC mass
D The diagnosis of PV requires the demonstration of an increase in RBC mass.
Pancytosis may also be seen in about two thirds of PV cases. Plasma volume is normal
or slightly reduced, and arterial O2 saturation is usually normal.
Features of secondary polycythemia include all of the following except:
A. Splenomegaly
B. Decreased O2 saturation
C. Increased RBC mass
D. Increased erythropoietin
A Splenomegaly is a feature of PV but not characteristic of secondary polycythemia. The
RBC mass is increased in both primary polycythemia (PV) and secondary
polycythemia. Erythropoietin is increased, and O2 saturation is decreased in secondary
polycythemia.
Erythrocytosis in relative polycythemia occurs because of:
A. Decreased arterial O2 saturation
B. Decreased plasma volume of circulating blood
C. Increased erythropoietin levels
D. Increased erythropoiesis in bone marrow
B Relative polycythemia is caused by reduction of plasma, rather than an increase in
RBC volume or mass. RBC mass is increased in both PV and secondary polycythemia,
but erythropoietin levels are high only in secondary polycythemia
In PV, what is characteristically seen in peripheral blood?
A. Panmyelosis
B. Pancytosis
C. Pancytopenia
D. Panhyperplasia
B PV is a myeloproliferative disorder characterized by uncontrolled proliferation of
erythroid precursors. However, production of all cell lines is usually increased.
Panhyperplasia is a term used to describe the cellularity of bone marrow in PV.
Leukocyte alkaline phosphatase (LAP) staining performed on a patient gives the
following results:
10(0) 48(1+) 38(2+) 3(3+) 1(4+)
Calculate the LAP score.
A. 100
B. 117
C. 137
D. 252
C One hundred mature neutrophils are counted and scored. The LAP score is calculated
as follows: (the number of 1+ cells × 1) + (2+ cells × 2) + (3+ cells × 3) + (4+ cells ×
4). That is, 48 + 76 + 9 + 4 = 137. The reference range is approximately 20 to 130.
CML is distinguished from leukemoid reaction by which of the following?
A. CML: low LAP; leukemoid: high LAP
B. CML: high LAP; leukemoid: low LAP
C. CML: high WBC; leukemoid: normal WBC
D. CML: high WBC; leukemoid: higher WBC
A CML causes a low LAP score, whereas an elevated or normal score occurs in a
leukemoid reaction. CML cannot be distinguished by WBC count because both CML
and leukemoid reaction have a high count.
Which of the following occurs in idiopathic myelofibrosis (IMF)?
A. Myeloid metaplasia
B. Leukoerythroblastosis
C. Fibrosis of bone marrow
D. All of these options
D Anemia, fibrosis, myeloid metaplasia, thrombocytosis, and leukoerythroblastosis
occur in IMF.
What influence does the Philadelphia (Ph1) chromosome have on the prognosis of
patients with CML?
A. It is not predictive
B. The prognosis is better if Ph1 is present
C. The prognosis is worse if Ph1 is present
D. The disease usually transforms into AML when Ph1 is present
B Ninety percent of patients with CML have the Ph1 chromosome. This appears as a
long-arm deletion of chromosome 22 but is actually a translocation between the long
arms of chromosomes 22 and 9. The ABL oncogene from chromosome 9 forms a
hybrid gene with the bcr region of chromosome 22. This results in production of a
chimeric protein with tyrosine kinase activity that activates the cell cycle. The
prognosis for CML is better if the Ph1 chromosome is present. Often, a second
chromosomal abnormality occurs in CML before a blast crisis.
Which of the following is (are) commonly found in CML?
A. Many teardrop-shaped cells
B. Intense LAP staining
C. A decrease in granulocytes
D. An increase in basophils
D CML is marked by an elevated WBC count demonstrating various stages of
maturation, hypermetabolism, and minimal LAP staining. An increase in basophils and
eosinophils is a common finding. Pseudo–Pelger–Huët cells and thrombocytosis may
be present. Bone marrow is hypercellular, with a high M:E ratio (e.g., 10:1).
In which of the following conditions does LAP show the least activity?
A. Leukemoid reactions
B. IMF
C. PV
D. CML
D CML shows the least LAP activity, whereas the LAP score is slightly to markedly
increased in each of the other states.
A striking feature of the peripheral blood of a patient with CML is:
A. Profusion of bizarre blast cells
B. Normal number of typical granulocytes
C. Presence of granulocytes at different stages of development
D. Pancytopenia
C The WBC count in CML is often higher than 100 × 109/L, and the peripheral blood
smear shows granulocyte progression from myeloblast to segmented neutrophil.
Which of the following is often associated with CML but not with AML?
A. Infections
B. WBCs greater than 20.0 × 109/L
C. Hemorrhage
D. Splenomegaly
D Splenomegaly is seen in greater than 90% of patients with CML, but it is not a
characteristic finding in AML. Infections, hemorrhage, and elevated WBC counts may
be seen in both CML and AML.
Multiple myeloma and Waldenström macroglobulinemia have all of the following in
common except:
A. Monoclonal gammopathy
B. Hyperviscosity of blood
C. Bence–Jones protein in urine
D. Osteolytic lesions
D Osteolytic lesions indicating destruction of bone, as evidenced by radiography, are
seen in multiple myeloma but not in Waldenström macroglobulinemia. In addition,
Waldenström macroglobulinemia gives rise to lymphocytosis, which does not occur in
multiple myeloma, and differs in the morphology of the malignant cells
What is the characteristic finding seen in the peripheral blood smear from a patient
with multiple myeloma?
A. Microcytic hypochromic cells
B. Intracellular inclusion bodies
C. Rouleaux
D. Hypersegmented neutrophils
C Rouleaux is present in patients with multiple myeloma as a result of increased
viscosity and decreased albumin:globulin ratio. Multiple myeloma is a plasma cell
dyscrasia that is characterized by overproduction of monoclonal immunoglobulin.
All of the following are associated with the diagnosis of multiple myeloma except:
A. Marrow plasmacytosis
B. Lytic bone lesions
C. Serum and/or urine M component (monoclonal protein)
D. Ph1 chromosome
D The Ph1 chromosome is a diagnostic marker for CML. Osteolytic lesions, monoclonal
gammopathy, and bone marrow infiltration by plasma cells constitute the triad of
diagnostic markers for multiple myeloma.
Multiple myeloma is most difficult to distinguish from:
A. CLL
B. Acute myelogenous leukemia
C. Benign monoclonal gammopathy
D. Benign adenoma
C Benign monoclonal gammopathies have peripheral blood findings similar to those in
myeloma. However, a lower concentration of monoclonal protein is usually seen.
There are no osteolytic lesions, and the plasma cells comprise less than 10% of
nucleated cells in bone marrow. About 30% become malignant, and therefore the term
monoclonal gammopathy of undetermined significance (MGUS) is the designation
used to describe this condition
The pathology of multiple myeloma includes which of the following?
A. Expanding plasma cell mass
B. Overproduction of monoclonal immunoglobulins
C. Production of osteoclast activating factor (OAF) and other cytokines
D. All of these options
D Mutated plasmablasts in bone marrow undergo clonal replication and expand the
plasma cell mass. Normal bone marrow is gradually replaced by malignant plasma
cells, leading to pancytopenia. Most malignant plasma cells actively produce
immunoglobulins. In multiple myeloma, the normally controlled and purposeful
production of antibodies is replaced by inappropriate production of even larger
amounts of useless immunoglobulin molecules. The normally equal production of light
chains and heavy chains may be imbalanced. The result is the release of excess free
light chains or free heavy chains. The immunoglobulins produced by a single clone of
myeloma cells are identical. Any abnormal production of identical antibodies is
referred to by the general term monoclonal gammopathy. Osteoclasts are bone cells
active in locally resorbing bone and releasing calcium into blood. Nearby osteoblasts
are equally active in utilizing the calcium in blood to form new bone. Multiple
myeloma interrupts this balance by the secretion of at least two substances. These are
interleukin-6 (IL-6) and OAF. As its name implies, OAF stimulates osteoclasts to
increase bone resorption and release of calcium, which lead to lytic lesions of the bone.
Waldenström macroglobulinemia is a malignancy of the:
A. Lymphoplasmacytoid cells
B. Adrenal cortex
C. Myeloblastic cell lines
D. Erythroid cell precursors
A Waldenström macroglobulinemia is a malignancy of lymphoplasmacytoid cells,
which manufacture IgM. Although the cells secrete immunoglobulin, they are not fully
differentiated into plasma cells and lack the characteristic perinuclear halo, deep
basophilia, and eccentric nucleus characteristic of classic plasma cells
Cells that exhibit positive staining with acid phosphatase and are not inhibited by
tartaric acid are characteristically seen in:
A. Infectious mononucleosis
B. Infectious lymphocytosis
C. Hairy cell leukemia (HCL)
D. T-cell acute lymphoblastic leukemia
C A variable number of malignant cells in HCL will stain positive with tartrate-resistant
acid phosphatase (TRAP+). Although this cytochemical reaction is fairly specific for
HCL, TRAP activity has occasionally been reported in B-cell leukemia and, rarely, T-
cell leukemia.
The JAK2(V617F) mutation may be positive in all of the following chronic
myeloproliferative disorders except:
A. ET
B. IMF
C. PV
D. CML
D The JAK2(V617F) mutation is negative in patients with CML. It may be positive in
patients with IMF (35%–57%), PV (65%–97%), and ET (23%–57%).
All of the following are major criteria for the 2008 WHO diagnostic criteria for ET
except:
A. PLT count 450 × 109/L or greater
B. Megakaryocyte proliferation with large and mature morphology and no or little
granulocyte or erythroid proliferation
C. Demonstration of JAK2(V617F) or other clonal marker
D. Evidence of clonality
D In the revised 2016 WHO classification, diagnosis of ET requires meeting four major
WHO diagnostic criteria, which include: PLT count 450 × 109/L or greater; bone
marrow proliferation of megakaryocyte lineage with large and mature megakaryocytes
with hyperlobulated nuclei and no or little granulocyte or erythroid proliferation; not
meeting WHO criteria for CML, PV, PMF, MDS, or other myeloid neoplasm; and
demonstration of JAK2(V617F), CALR, or MPL mutation or other clonal marker.
Diagnosis can also be made with the first three major criteria and one minor criterion,
either evidence of clonality or absence of reactive thrombocytosis
A 19-year-old man came to the emergency department with severe joint pain, fatigue,
cough, and fever. Review the following laboratory results:
WBCs 21.0 × 10^9/L
RBCs 3.23 × 10^12/L
Hgb 9.6 g/dL
PLT 252 × 10^9/L
Differential: 17 band neutrophils; 75 segmented neutrophils; 5 lymphocytes; 2 monocytes; 1
eosinophil; 26 NRBCs
What is the corrected WBC count?
A. 8.1 × 10^9/L
B. 16.7 × 10^9/L
C. 21.0 × 10^9/L
D. 80.8 × 10^9/L
B The formula for correcting the WBC count for the presence of NRBCs is:
Total WBC × 100 or (21.0 × 100) ÷ 126 = 16.7 × 10^9/L
where total WBC = WBCs × 10^9/L, 100 is the number of WBCs counted in the
differential, and 126 is the sum of NRBCs plus WBCs counted in the differential.
A manual WBC count is performed. Eighty WBCs are counted in the four large corner
squares of a Neubauer hemacytometer. The dilution is 1:100. What is the total WBC
count?
A. 4.0 × 10^9/L
B. 8.0 × 10^9/L
C. 20.0 × 10^9/L
D. 200.0 × 10^9/L
cells counted × 10 (depth factor) × dilution factor ÷ area counted in mm2 or
C The formula for calculating manual cell counts using a hemacytometer is: # cells counted × 10 (depth factor) × dilution factor ÷ area counted in mm2 or
(80 × 10 × 100) ÷ 4 = 20,000/μL
or
20.0 × 10^9/L
A manual RBC count is performed on pleural fluid. The RBC count in the large center
square of the Neubauer hemacytometer is 125, and the dilution is 1:200. What is the
total RBC count?
A. 27.8 × 10^9/L
B. 62.5 × 10^9/L
C. 125.0 × 10^9/L
D. 250.0 × 10^9/L
D Regardless of the cell or fluid type, the formula for calculating manual cell counts
using a hemacytometer is:
# cells counted × 10 (depth factor) × dilution factor ÷ area counted in mm2
or
(125 × 10 × 200) ÷ 1 = 250,000/μL
or
250.0 × 10^9/L
Review the scatterplot of WBCs shown. Which section of the scatterplot denotes the
number of monocytes?
A. A
B. B
C. C
D. D
A WBC identification is facilitated by analysis of the impedance, conductance, and light-
scattering properties of WBCs. The scatterplot represents the relationship between
volume (x-axis) and light scatter (y-axis). Monocytes account for the dots in section A,
neutrophils are represented in section B, eosinophils are represented in section C, and
lymphocytes are denoted in section D.
Review the following automated CBC values.
WBC = 17.5 × 10^9/L (flagged) MCV = 86.8 fL
RBC = 2.89 × 10^12/L MCH = 28.0 pg
Hgb = 8.1 g/dL MCHC = 32.3%
Hct = 25.2% PLT = 217 × 10^9/L
Many sickle cells were observed on review of the peripheral blood smear. On the basis
of this finding and the results provided, what automated parameter of this patient is
most likely inaccurate, and what follow-up test should be done to accurately assess this
parameter?
A. MCV/perform reticulocyte count
B. Hct/perform manual Hct
C. WBC/perform manual WBC count
D. Hgb/perform serum–saline replacement
C When an automated WBC count is performed using a hematology analyzer, RBCs are
lysed to allow enumeration of WBCs. Sickle cells are often resistant to lysis within the
limited time frame (less than 1 minute), during which the RBCs are exposed to the
lysing reagent and the WBCs are subsequently counted. As a result, the nonlysed
RBCs are counted along with WBCs, and this falsely increases the WBC count. When
an automated cell counting analyzer indicates a review flag for the WBC count and
sickle cells are noted on peripheral blood smear analysis, a manual WBC count must
be performed. The manual method allows optimal time for sickle cell lysis and
accurate enumeration of WBCs.
Review the following CBC results for a 2-day-old infant:
WBC = 15.2 × 109/L MCV = 105 fL
RBC = 5.30 × 1012/L MCH = 34.0 pg
Hgb = 18.5 g/dL MCHC = 33.5%
Hct = 57.9% PLT = 213 × 10^9/L
These results indicate:
A. Macrocytic anemia
B. Microcytic anemia
C. Liver disease
D. Normal values for a 2-day-old infant
D During the first week of life, an infant has an average Hct of 55 mL/dL. This value
drops to a mean of 43 mL/dL by the first month of life. The mean MCV of the first
week is 108 fL; after 2 months, the average MCV is 96 fL. The mean WBC count
during the first week is approximately 18 × 10^9/L, and this drops to an average of 10.8
× 10^9/L after the first month. The PLT count in newborns falls within the same normal
range as in adults.
Review the following scatterplot, histograms, and automated values for a 21-year-old
college student.
WBC differential: 5 band neutrophils; 27 segmented neutrophils; 60 atypical lymphocytes; 6
monocytes; 1 eosinophil; 1 basophil
What is the presumptive diagnosis?
A. Infectious mononucleosis
B. Monocytosis
C. CLL
D. β-Thalassemia
A Lymphocytosis with numerous atypical lymphocytes is a hallmark finding consistent
with the diagnosis of infectious mononucleosis. The automated results demonstrated
abnormal WBC subpopulations, specifically lymphocytosis as well as monocytosis.
However, on peripheral blood smear examination, 60 atypical lymphocytes and only
six monocytes were noted. Atypical lymphocytes are often misclassified by automated
cell counters as monocytes. Therefore, the automated analyzer differential must not be
released and the manual differential count must be relied on for diagnostic
interpretation.
Review the following scatterplot, histograms, and automated values for a 61-year-old
woman.
WBC differential: 14 band neutrophils; 50 segmented neutrophils; 7 lymphocytes; 4 monocytes;
10 metamyelocytes; 8 myelocytes; 1 promyelocyte; 3 eosinophils; 3 basophils; 2 NRBCs/100
WBCs
What is the presumptive diagnosis?
A. Leukemoid reaction
B. CML
C. AML
D. Megaloblastic leukemia
B The “+++++” on the printout indicates that the WBC count exceeds the upper linearity
of the analyzer (greater than 99.9 × 10^9/L). This markedly elevated WBC count,
combined with the spectrum of immature granulocytic cells seen on peripheral blood
smear examination, indicates the diagnosis of CML
Review the automated results from the previous question. Which parameters can be
released without further follow-up verification procedures?
A. WBC and relative percentages of WBC populations
B. RBCs and PLTs
C. Hgb and Hct
D. None of the automated counts can be released without follow-up verification
D All of the automated results have “R,” or review, flags indicated; none can be released
without manual verification procedures. The specimen must be diluted to bring the
WBC count within the linearity range of the analyzer. When enumerating the RBC
count, the analyzer does not lyse the WBCs and, in fact, includes them in the RBC
count. As such, the RBC count is falsely elevated because of the increased number of
WBCs. Therefore, after an accurate WBC count has been obtained, this value can be
subtracted from the RBC count to obtain the true RBC count. For example, using the
values for this patient:
Step 1: Obtain an accurate WBC count by diluting the sample 1:10.
WBC = 41.0 × 10 (dilution) = 410 × 10^9/L
Step 2: Convert this value to cells per 10^12 to subtract from the RBC count.
410 × 10^9/L = 0.41 × 10^12/L
Step 3: Subtract the WBC count from the RBC count to get the accurate RBC count.
3.28 (original RBC) – 0.41 (true WBC) = 2.87 × 10^12/L = accurate RBC
The Hct may be obtained by microhematocrit centrifugation. The true MCV may be
obtained by using the standard formula:
MCV = (Hct ÷ RBC) × 10
where RBC = RBC count in millions per microliter.
Additionally, the PLT count must be verified by smear estimate or performed
manually.
Refer to the following scatterplot, histograms, and automated values for a 45-year-old
man. What follow-up verification procedure is indicated before these results can be
released?
A. Redraw blood sample using a sodium citrate tube; multiply PLTs × 1.11
B. Dilute WBCs 1:10; multiply × 10
C. Perform plasma blank Hgb to correct for lipemia
D. Warm specimen at 37°C for 15 minutes; rerun specimen
A The PLT clumping phenomenon is often induced in vitro by the anticoagulant EDTA.
Redrawing a sample from the patient by using a sodium citrate tube usually corrects
this phenomenon and allows for accurate PLT enumeration. The PLT count must be
multiplied by 1.11 to adjust for the amount of sodium citrate. PLT clumps cause a
spurious decrease in the PLT count by automated methods. The WBC value has an “R”
(review) flag because the PLT clumps have been falsely counted as WBCs; therefore, a
manual WBC count is indicated.
Refer to the following scatterplot, histograms, and automated values for a 52-year-old
woman. What follow-up verification procedure is indicated before these results can be
released?
A. Redraw specimen using a sodium citrate tube; multiply PLTs × 1.11
B. Dilute WBCs 1:10; multiply × 10
C. Perform plasma blank Hgb to correct for lipemia
D. Warm the specimen at 37°C for 15 minutes; rerun the specimen
D The presence of high-titer cold agglutinin in a patient with cold AIHA will interfere
with automated cell counting. The most remarkable findings are falsely elevated MCV,
MCH, and MCHC, as well as falsely decreased RBC count. The patient’s RBCs will
quickly agglutinate in vitro when exposed to ambient temperatures below body
temperature. To correct for this phenomenon, the EDTA tube should be incubated at
37°C for 15 to 30 minutes, and then the specimen should be rerun.
Refer to the following scatterplot, histograms, and automated values for a 33-year-old
woman. What follow-up verification procedure is indicated before these results can be
released?
A. Perform a manual Hct and redraw the sample using a sodium citrate tube; multiply PLTs
× 1.11
B. Dilute WBCs 1:10; multiply × 10
C. Perform plasma blank Hgb to correct for lipemia
D. Warm the specimen at 37°C for 15 minutes; rerun the specimen
C The rule of thumb regarding the Hgb/Hct correlation dictates that Hgb × 3 ≈ Hct (±
3). This rule has been violated in this patient; therefore, a follow-up verification
procedure is indicated. Additionally, MCHC is markedly elevated in these results, and
an explanation for falsely increased Hgb should be sought. Lipemia can be visualized
by centrifuging the EDTA tube and observing for a milky white plasma. To correct for
the presence of lipemia, a plasma Hgb value (baseline Hgb) should be ascertained by
using the patient’s plasma and subsequently subtracted from the original falsely
elevated Hgb value. The following formula can be used to correct for lipemia:
Whole blood Hgb – [(Plasma Hgb) (1 – Hct/100)] = Corrected Hgb
Refer to the following scatterplot, histograms, and automated values for a 48-year-old
man. What follow-up verification procedure is indicated before the five-part WBC
differential results can be released?
A. Dilute WBCs 1:10; multiply × 10
B. Redraw the sample using a sodium citrate tube; multiply WBCs × 1.11
C. Prepare buffy coat peripheral blood smears, and perform a manual differential
D. Warm specimen at 37°C for 15 minutes; rerun specimen
C The markedly decreased WBC count (0.2 × 10^9/L) indicates that a manual differential
is necessary and that very few leukocytes will be available for differential cell
counting. To increase the yield and thereby facilitate counting, differential smears
should be prepared by using the buffy coat technique.
Review the following CBC results for a 70-year-old man:
WBC = 58.2 × 10^9/L MCV = 98 fL
RBC = 2.68 × 10^12/L MCH = 31.7 pg
Hgb = 8.5 g/dL MCHC = 32.6%
Hct = 26.5 mL/dL% PLT = 132 × 10^9/L
Differential: 96 lymphocytes; 2 band neutrophils; 2 segmented neutrophils; 25 smudge cells/100
WBCs
What is the most likely diagnosis on the basis of these values?
A. ALL
B. CLL
C. Infectious mononucleosis
D. Myelodysplastic syndrome
B CLL is a disease of older adults, classically associated with an elevated WBC count
and relative and absolute lymphocytosis. CLL is twice as common in men, and smudge
cells (WBCs with little or no surrounding cytoplasm) are usually present in the
peripheral blood smear. CLL may occur with or without anemia or thrombocytopenia.
The patient’s age and lack of blasts rule out ALL. Similarly, the patient’s age and lack
of atypical lymphocytes make infectious mononucleosis unlikely. Myelodysplastic
syndromes may involve the erythroid, granulocytic, or megakaryocytic cell lines but
not the lymphoid cells.
Refer to the following scatterplot, histograms, and automated values for a 28-year-old
woman who had undergone preoperative laboratory testing. A manual WBC
differential was requested by her physician. The WBC differential was not significantly
different from the automated five-part differential; however, the medical laboratory
scientist noted 3+ elliptocytes/ovalocytes while reviewing the RBC morphology. What is
the most likely diagnosis for this patient?
A. DIC
B. HE (ovalocytosis)
C. Cirrhosis
D. Hgb C disease
B The finding of ovalocytes as the predominant RBC morphology in peripheral blood is
consistent with the diagnosis of HE, or ovalocytosis. This disorder is relatively
common and can range in severity from an asymptomatic carrier state to homozygous
HE with severe hemolysis. The most common clinical subtype is associated with no or
minimal hemolysis. Therefore, HE is usually associated with a normal RBC histogram
and cell indices and will go unnoticed without microscopic evaluation of the peripheral
blood smear.
A 25-year-old woman presented with symptoms of jaundice, acute cholecystitis, and an
enlarged spleen. On investigation, numerous gallstones were discovered. Review the
following CBC results:
WBC = 11.1 × 10^9/L MCV = 100 fL
RBC = 3.33 × 10^12/L MCH = 34.5 pg
Hgb = 11.5 g/dL MCHC = 37.5%
Hct = 31.6 mL/dL PLT = 448 × 10^9/L
WBC differential: 13 band neutrophils; 65 segmented neutrophils; 15 lymphocytes; 6
monocytes; 1 eosinophil RBC morphology: 3+ spherocytes, 1+ polychromasia
What follow-up laboratory test would provide valuable information for this patient?
A. Osmotic fragility test
B. Hgb electrophoresis
C. G6PD assay
D. Methemoglobin reduction test
A The osmotic fragility test is indicated as a confirmatory test for the presence of
numerous spherocytes, and individuals with HS have an increased osmotic fragility.
MCHC is elevated in greater than 50% of patients with spherocytosis, and this
parameter can be used as a clue to the presence of HS. Spherocytes have a decreased
surface:volume ratio, probably resulting from mild cellular dehydration.
Refer to the following scatterplot, histograms, and automated values for a 53-year-old
man who had undergone preoperative laboratory testing. What is the most likely
diagnosis for this patient?
A. IDA
B. PV
C. Sideroblastic anemia
D. β-thalassemia minor
D β-thalassemia minor can be easily detected by noting an abnormally elevated RBC
count and Hct that does not correlate with the elevated RBC count, in conjunction with
a decreased MCV. Although thalassemia and IDA are both microcytic, hypochromic
processes, thalassemia can be differentiated from IDA because in IDA the RBC count,
Hgb, and Hct values are usually decreased along with MCV. Although the RBC count
is increased in PV, Hct must also be greater than 50% for a diagnosis of PV to be
considered.
Review the following CBC results:
WBC = 11.0 × 10^9/L MCV = 85.0 fL
RBC = 3.52 × 10^12/L MCH = 28.4 pg
Hgb = 10.0 g/dL MCHC = 33.4%
Hct = 29.9 mL/dL PLT = 155 × 10^9/L
12 NRBCs/100 WBCs
RBC morphology: Moderate polychromasia, 3+ target cells, few schistocytes
Which of the following additional laboratory tests would yield informative diagnostic
information for this patient?
A. Osmotic fragility test
B. Hgb electrophoresis
C. Sugar water test
D. Bone marrow examination
B The findings of moderate anemia, numerous target cells seen on the peripheral blood
smear, and the presence of NRBCs are often associated with hemoglobinopathies. Hgb
electrophoresis at alkaline pH is a commonly performed test to correctly diagnose the
type of hemoglobinopathy.
Which of the following initiates in vivo coagulation by activation of factor VII?
A. Protein C
B. Tissue factor (TF)
C. Plasmin activator
D. Thrombomodulin (TM)
B In vivo, activation of coagulation occurs on the surface of activated platelets (PLTs) or
cells that have TF. TF is found on the surface of many cells outside the vascular
system (extrinsic). On vascular injury, TF is exposed to the vascular system. TF has
high affinity for factors VII and VIIa. TF activates factor VII to VIIa and forms TF–
VIIa complex. TF–VIIa complex in the presence of calcium ion (Ca2+) and PLT
phospholipid activates factor IX to factor IXa and factor X to factor Xa. Factor Xa
forms a complex with cofactor Va (Xa–Va) on the surface of the activated PLTs.
Factor Xa–Va complex in the presence of Ca2+ and PLT phospholipid converts
prothrombin (factor II) to thrombin (IIa). Thrombin acts on soluble plasma fibrinogen
to form a fibrin clot, which is stabilized by activated factor XIII (XIIIa). In addition,
activated factor IX (IXa) forms a complex with activated cofactor VIII (VIIIa) on the
surface of the activated PLTs. Factor IXa–VIIIa complex in the presence of Ca2+ and
PLT phospholipid converts factor X to Xa with the end products of thrombin and fibrin
clot, as discussed previously. The classical description of intrinsic, extrinsic, and
common pathways does not take place in vivo. The concept of these three pathways is
used to explain clot formation in laboratory tests. Activated thromboplastin time
(APTT) is determined by the intrinsic and common pathways, whereas prothrombin
time (PT) is determined by the extrinsic and common pathways. The extrinsic pathway
is so named because TF is derived from extravascular cells.
Which of the following clotting factors plays a role in clot formation in vitro, but not in
vivo?
A. Factor VIIa
B. Factor IIa
C. Factor XIIa
D. Factor Xa
C Factor XIIa does not play a role in coagulation in vivo; however, in vitro, the
deficiency of this factor causes prolonged APTT. In vitro, factor XII is activated by
substances, such as glass, Kaolin, and ellagic acid, and in vivo it may be activated by
exposure to a negatively charged cell surface membrane, such collagen, as well as to
kallikrein and high-molecular-weight kininogen (HMWK). In vivo, factor XIIa plays
an important role in the fibrinolytic system by activating plasminogen to plasmin.
Plasmin degrades the fibrin clot at the site of injury. Deficiency of factor XII is
associated with thrombosis and not with bleeding. Factors VIIa, Xa, and IIa play a role
in vivo and in vitro.
The anticoagulant of choice for most routine coagulation studies is:
A. Sodium oxalate
B. Sodium citrate
C. Heparin
D. Ethylenediaminetetraacetic acid (EDTA)
B The anticoagulant of choice for most coagulation procedures is sodium citrate (3.2%).
Because factors V and VIII are more labile in sodium oxalate, heparin neutralizes
thrombin, and EDTA inhibits thrombin’s action on fibrinogen, these anticoagulants are
not used for routine coagulation studies.
Which anticoagulant:blood ratio is correct for coagulation procedures?
A. 1:4
B. 1:5
C. 1:9
D. 1:10
C The optimal anticoagulant:blood ratio is one part anticoagulant to nine parts blood. The
anticoagulant supplied in this amount is sufficient to bind all the available calcium,
thereby preventing clotting.
Which results would be expected for PT and APTT in a patient with polycythemia?
A. Both prolonged
B. Both shortened
C. Normal PT, prolonged APTT
D. Both normal
A The volume of blood in a polycythemic patient contains so little plasma that excess
anticoagulant remains and is available to bind to reagent calcium, thereby resulting in
prolongation of PT and APTT. For more accurate results, the plasma:anticoagulant
ratio can be modified by decreasing the amount of anticoagulant in the collection tube
by using the following formula: (0.00185)(V)(100–H) = C, where V = blood volume in
milliliters (mL); H = patient’s hematocrit (Hct); and C = volume (mL) of
anticoagulant. A new sample should be drawn to rerun the PT and APTT tests.
Which reagents are used in the PT test?
A. Thromboplastin and sodium chloride
B. Thromboplastin and potassium chloride
C. Thromboplastin and calcium
D. Actin and calcium chloride
C Thromboplastin and calcium (combined into a single reagent) replace tissue
thromboplastin and calcium necessary, in vivo, to activate factor VII to factor VIIa.
This ultimately generates thrombin from prothrombin via the coagulation cascade.
Which test would be abnormal in a patient with factor X deficiency?
A. PT only
B. APTT only
C. PT and APTT
D. Thrombin time (TT)
C Factor X is involved in the common pathway of the coagulation cascade; therefore, its
deficiency prolongs both PT and APTT. Activated factor X along with activated factor
V in the presence of calcium and platelet factor 3 (PF3) converts prothrombin (factor
II) to the active enzyme thrombin (factor IIa).
Which clotting factor is not measured by the PT and APTT tests?
A. Factor VIII
B. Factor IX
C. Factor V
D. Factor XIII
D Factor XIII is not measured by PT or APTT. Factor XIII (fibrin stabilizing factor) is a
transamidase. It creates covalent bonds between fibrin monomers, which are formed
during the coagulation process, to produce a stable fibrin clot. In the absence of factor
XIII, the hydrogen bonded fibrin polymers are unstable and, therefore, soluble in 5M
urea or in 1% monochloroacetic acid.
A modification of which procedure can be used to measure fibrinogen?
A. PT
B. APTT
C. TT
D. Fibrin degradation products
C Fibrinogen can be quantitatively measured by modification of the TT by diluting the
plasma because the thrombin clotting time of diluted plasma is inversely proportional
to the concentration of fibrinogen (principle of Clauss method)
Which of the following characterizes vitamin K?
A. It is required for biological activity of fibrinolysis
B. Its activity is enhanced by heparin therapy
C. It is required for carboxylation of glutamate residues of some coagulation factors
D. It is made by endothelial cells
C Vitamin K is necessary for activation of vitamin K–dependent clotting factors (II,
VII, IX, and X). This activation is accomplished by carboxylation of glutamic acid
residues of the inactive clotting factors. The activity of vitamin K is not enhanced by
heparin therapy. Vitamin K is present in a variety of foods and is also the only vitamin
made by the organisms living in the intestine.
Which fragments of fibrin clot degradation are measured by the D-dimer test?
A. Fragments X and Y
B. Fibrinopeptide A and B
C. Fragments D and E
D. The D-D domains
D D-dimer is a specific product resulting from digestion of cross-linked fibrin only. It
consists of two D domains called D-D fragment and is a marker for thrombosis and
fibrinolysis. In the D-dimer test, monoclonal antibody is directed against D-dimer
antigen by using a variety of automated instruments. The D-dimer test is used to
diagnose acute and chronic disseminated intravascular coagulation (DIC) and to rule
out thromboembolic disorders. Fragments X, Y, D, and E are produced by the action of
plasmin on fibrinogen and fibrin. Polypeptide A and B are produced by the proteolytic
action of thrombin on fibrinogen to form a fibrin clot.
Which of the following clotting factors are measured by the APTT test?
A. Factors II, VII, IX, X
B. Factors VII, X, V, II, I
C. Factors XII, XI, IX, VIII, X, V, II, I
D. Factors XII, VII, X, V, II, I
C The APTT test evaluates the clotting factors in the intrinsic pathway (XII, XI, IX, and
VIII) as well as those in the common pathway (X, V, II, and I).
Which coagulation test(s) would be abnormal in a patient with vitamin K deficiency?
A. PT only
B. PT and APTT
C. Fibrinogen level
D. TT
B Patients with vitamin K deficiency exhibit decreased production of functional
prothrombin proteins (factors II, VII, IX, and X). Decreased levels of these factors
prolong both PT and APTT.
Which of the following is correct regarding the international normalized ratio (INR)?
A. It uses the international sensitivity ratio (ISR)
B. It standardizes PT results
C. It standardizes APTT results
D. It is used to monitor heparin therapy
B INR is used to standardize PT results to adjust for the differences in thromboplastin
reagents made by different manufacturers and used by various institutions. The INR
calculation uses the international sensitivity index (ISI) value and is used to monitor an
oral anticoagulant, such as warfarin. INR is not used to standardize APTT testing.
Which of the following is referred to as an endogenous activator of plasminogen?
A. Streptokinase
B. Transamidase
C. Tissue plasminogen activator (tPA)
D. tPA inhibitor
C tPA is an endogenous (produced in the body) activator of plasminogen. It is released
from the endothelial cells by the action of protein C. It converts plasminogen to
plasmin. Streptokinase is an exogenous (not made in the body) activator of
plasminogen.
Which protein is the primary inhibitor of the fibrinolytic system?
A. Protein C
B. Protein S
C. α2-Antiplasmin
D. α2-Macroglobulin
C α2-Antiplasmin is the main inhibitor of plasmin. It inhibits plasmin by forming a 1:1
stoichiometric complex with any free plasmin in plasma and, thus, prevents binding of
plasmin to fibrin and fibrinogen
Which of the following statements is correct regarding the D-dimer test?
A. Levels are decreased in DIC
B. Test detects polypeptides A and B
C. Test detects fragments D and E
D. Test has a negative predictive value
D The D-dimer assay evaluates fibrin degradation. It is a nonspecific screening test that
shows increased values in many conditions in which fibrinolysis is increased, such as
DIC and fibrinolytic therapy. The D-dimer test is widely used to rule out thrombosis
and thrombotic activities. The negative predictive value of a test is the probability that
a person with a negative result is free of the disease that the test is meant to detect.
Therefore, a negative D-dimer test result rules out thrombosis, and further laboratory
investigations are not required
A protein that plays a role in both coagulation and PLT aggregation is:
A. Factor I
B. Factor VIII
C. Factor IX
D. Factor XI
A Factor I (fibrinogen), along with the glycoprotein IIb–IIIa complex, is necessary for
PLT aggregation. Factor I is also a substrate in the common pathway of coagulation.
Thrombin acts on fibrinogen to form fibrin clots.
A standard 4.5-mL blue-top tube filled with 3.0 mL of blood was submitted to the
laboratory for PT and APTT tests. The sample is from a patient undergoing surgery the
following morning for a tonsillectomy. Which of the following is the necessary course of
action by the medical laboratory scientist?
A. Run both tests in duplicate and report the average result
B. Reject the sample and request a new sample
C. Report the PT result
D. Report the APTT result
B A 4.5-mL blue-top tube contains 4.5 mL blood + 0.5 mL sodium citrate. The tube
should be 90% full. A tube with 3.0 mL blood should be rejected because the quantity
is not sufficient (QNS). QNS samples alter the necessary blood:anticoagulant ratio
(9:1). The excess anticoagulant in a QNS sample binds to the reagent calcium,
resulting in prolongation of PT and APTT
Which statement is correct regarding sample storage for the PT test?
A. Stable for 24 hours if the sample is capped
B. Stable for 24 hours if the sample is refrigerated at 4°C
C. Stable for 4 hours if the sample is stored at 4°C
D. Should be run within 8 hours
A According to Clinical Laboratory Standards Institute (CLSI) guidelines, plasma
samples for PT testing, if capped, are stable for 24 hours at room temperature.
Refrigerating the sample causes cold activation of factor VII and, therefore, shortened
PT results. APTT samples are stable for 4 hours if stored at 4°C.
In primary fibrinolysis, the fibrinolytic activity results in response to:
A. Increased fibrin formation
B. Spontaneous activation of fibrinolysis
C. Increased fibrin monomers
D. DIC
B Primary fibrinolysis is a rare pathological condition in which spontaneous systemic
fibrinolysis occurs. Plasmin is formed in the absence of coagulation activation and clot
formation. Primary fibrinolysis is associated with increased production of plasminogen
and plasmin, decreased plasmin removal from the circulation, and spontaneous
bleeding.
Plasminogen deficiency is associated with:
A. Bleeding
B. Thrombosis
C. Increased fibrinolysis
D. Increased coagulation
B Plasminogen deficiency is associated with thrombosis. Plasminogen is an important
component of the fibrinolytic system. Plasminogen is activated to plasmin, which is
necessary for the degradation of fibrin clots to prevent thrombosis. When plasminogen
is deficient, plasmin is not formed, causing a defect in the clot lysing processes.
Which of the following clotting factors are activated by thrombin that is generated by
tissue pathway (TF-VIIa)?
A. Factors XII, XI
B. Factors XII, I
C. Factors I, II
D. Factors V, VIII
D Factors V and VIII are activated by the thrombin that is generated by the action of
TF-VIIa on factor X to form factor Xa. Factor Xa forms a complex with factor Va on
the PLT surfaces. Factor Xa–Va complex in the presence of phospholipid and Ca2+
transform more prothrombin to thrombin.
Which substrate is used in a chromogenic factor assay?
A. p-nitroaniline (pNa)
B. Chlorophenol red
C. Prussian blue
D. Ferricyanide
A The chromogenic, or amidolytic, assays use a color-producing substance, known as
chromophore. The chromophore used for the coagulation laboratory is pNa. pNa is
bound to a synthetic oligopeptide substrate. The protease cleaves the chromogenic
substrate at the site binding the oligopeptide to the pNa, which results in release of
pNa. Free pNa has a yellow color; the color intensity of the solution is proportional to
protease activity and is measured by a photodetector at 405 nm.
Which of the following antibodies is used in the D-dimer assay?
A. Polyclonal antibody directed against X and Y fragments
B. Polyclonal antibody directed against D-dimer
C. Monoclonal antibody against D and E fragments
D. Monoclonal antibody against D-dimer
D The D-dimer is the fibrin degradation product generated by the action of plasmin on
cross-linked fibrin formed by XIIIa. The patient’s plasma is mixed with latex particles
coated with monoclonal antibodies against D-domains. The test can be automated, or
performed manually on a glass slide by looking macroscopically for agglutination.
Enzyme-linked immunosorbent assay (ELISA) methods are also available. Normal D-
dimer in plasma is less than 2 ng/mL. Increased levels of D-dimer are associated with
DIC, thrombolytic therapy, venous thrombosis, and thromboembolic disorders. The D-
dimer assay has a 90% to 95% negative predictive value and has been used to rule out
thrombosis and thromboembolic disorders.
Thrombotic thrombocytopenic purpura (TTP) is characterized by:
A. Prolonged PT
B. Increased PLT aggregation
C. Thrombocytosis
D. Prolonged APTT
B TTP is a quantitative PLT disorder associated with increased intravascular PLT
activation and aggregation resulting in thrombocytopenia. PT and APTT results are
normal in TTP.
Thrombocytopenia may be associated with:
A. Splenectomy
B. Hypersplenism
C. Acute blood loss
D. Increased proliferation of pluripotent stem cells
B Hypersplenism is associated with thrombocytopenia. In this condition, up to 90% of
PLTs can be sequestered in the spleen, causing decreases in circulatory PLTs.
Splenectomy, acute blood loss, and increased proliferation of pluripotent stem cells are
associated with thrombocytosis
Aspirin prevents PLT aggregation by inhibiting the action of which enzyme?
A. Phospholipase
B. Cyclo-oxygenase
C. Thromboxane A2 (TXA2) synthetase
D. Prostacyclin synthetase
B Aspirin prevents PLT aggregation by inhibiting the activity of the enzyme cyclo-
oxygenase. This inhibition prevents the formation of TXA2, which serves as a potent
PLT aggregator.
Normal PLT adhesion depends on:
A. Fibrinogen
B. Glycoprotein Ib
C. Glycoprotein IIb–IIIa complex
D. Calcium
B Glycoprotein Ib is a PLT receptor for VWF. Glycoprotein Ib and VWF are both
necessary for a normal PLT adhesion. Other proteins that play a role in PLT adhesion
are glycoproteins V and IX.
Which of the following test results is normal in a patient with classic von Willebrand
disease?
A. PLT aggregation
B. APTT
C. PLT count
D. Factor VIII:C and von Willebrand factor (VWF) levels
C Von Willebrand disease is an inherited, qualitative PLT disorder that results in
increased bleeding, prolonged APTT, and decreased factor VIII:C and VWF levels.
The PLT count and morphology are generally normal in von Willebrand disease, but
PLT aggregation in the PLT function assay is abnormal.
Bernard–Soulier syndrome is associated with:
A. Decreased factor IX
B. Decreased factor VIII
C. Thrombocytopenia and giant PLTs
D. Abnormal PLT function test results
C Bernard–Soulier syndrome is associated with thrombocytopenia and giant PLTs. It is a
qualitative PLT disorder caused by the deficiency of glycoprotein Ib. In Bernard–
Soulier syndrome, PLT aggregation in the PLT function assay is abnormal. Factor VIII
and IX assays are not indicated for this diagnosis
When performing PLT aggregation studies, which set of PLT aggregation results would
most likely be associated with Bernard–Soulier syndrome?
A. Normal PLT aggregation to collagen, adenosine diphosphate (ADP), and ristocetin
B. Normal PLT aggregation to collagen, ADP, and epinephrine (EPI); decreased aggregation
to ristocetin
C. Normal PLT aggregation to EPI and ristocetin; decreased aggregation to collagen and
ADP
D. Normal PLT aggregation to EPI, ristocetin, and collagen; decreased aggregation to ADP
B Bernard–Soulier syndrome is a disorder of PLT adhesion caused by deficiency of
glycoprotein Ib. PLT aggregation is normal in response to collagen, ADP, and EPI but
abnormal in response to ristocetin
Which set of PLT responses would be most likely associated with Glanzmann
thrombasthenia?
A. Normal PLT aggregation to ADP and ristocetin; decreased aggregation to collagen
B. Normal PLT aggregation to collagen; decreased aggregation to ADP and ristocetin
C. Normal PLT aggregation to ristocetin; decreased aggregation to collagen, ADP, and EPI
D. Normal PLT aggregation to ADP; decreased aggregation to collagen and ristocetin
C Glanzmann thrombasthenia is a disorder of PLT aggregation. PLT aggregation is
normal in response to ristocetin, but abnormal in response to collagen, ADP, and EPI.
Which of the following is a characteristic of acute immune thrombocytopenic purpura?
A. Spontaneous remission within a few weeks
B. Predominantly seen in adults
C. Nonimmune PLT destruction
D. Insidious onset
A Acute immune thrombocytopenic purpura is an immune-mediated disorder found
predominantly in children. It is commonly associated with infection (primarily viral). It
is characterized by abrupt onset, and spontaneous remission usually occurs within
several weeks.
TTP differs from DIC in that:
A. APTT is normal in TTP but prolonged in DIC
B. Schistocytes are not present in TTP but are present in DIC
C. PLT count is decreased in TTP but normal in DIC
D. PT is prolonged in TTP but decreased in DIC
A TTP is a PLT disorder in which PLT aggregation increases, resulting in
thrombocytopenia. Schistocytes are present in TTP as a result of microangiopathic
hemolytic anemia (MAHA); however, the PT and APTT are both normal. In DIC, the
PT and APTT are both prolonged, the PLT count is decreased, and schistocytes are
seen in the peripheral blood smear.
Several hours after birth, a baby boy develops petechiae and purpura and hemorrhagic
diathesis. The PLT count is 18 × 10^9/L. What is the most likely explanation for the low
PLT count?
A. Drug-induced thrombocytopenia
B. Secondary thrombocytopenia
C. Neonatal alloimmune thrombocytopenia
D. Neonatal DIC
C Neonatal alloimmune thrombocytopenia is similar to the hemolytic disease of the
fetus and newborn. It results from immunization of the mother by fetal PLT antigens.
The offending antibodies are commonly anti-PLT antigen A1 (PlA1), also referred to as
human platelet antigen (HPA) 1a. These alloantibodies are directed against
glycoproteins IIb/IIIa, Ib/IX, Ia/IIb, and CD 109. Maternal antibodies cross the
placenta, resulting in thrombocytopenia in the fetus.
Which of the following is associated with post-transfusion purpura (PTP)?
A. Nonimmune thrombocytopenia/alloantibodies
B. Immune-mediated thrombocytopenia/alloantibodies
C. Immune-mediated thrombocytopenia/autoantibodies
D. Nonimmune-mediated thrombocytopenia/autoantibodies
B PTP is a rare form of alloimmune thrombocytopenia characterized by severe
thrombocytopenia occurring after transfusion of blood or blood products. PTP is
caused by antibody-related PLT destruction in previously immunized patients. In the
majority of cases, the alloantibody produced is against PlA1 (HPA-1a).
Hemolytic uremic syndrome (HUS) is associated with:
A. Fever, thrombocytosis, anemia, and renal failure
B. Fever, granulocytosis, and thrombocytosis
C. Escherichia coli 0157:H7
D. Leukocytosis and thrombocytosis
C HUS is caused by E. coli 0157:H7. It is associated with ingestion of E. coli–
contaminated foods and is commonly seen in children. The clinical manifestations in
HUS are fever, diarrhea, thrombocytopenia, MAHA, and renal failure.
