HEMA Harr 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. A false increase in hematocrit (Hct) value
Explanation: Insufficient centrifugation does not pack down the red blood cells; therefore, the Hct, which is the volume of packed cells, will increase.
Variation in red cell size observed on the
peripheral smear is described as:
A. Anisocytosis
B. Hypochromia
C. Poikilocytosis
D. Pleocytosis
A. Anisocytosis
Which of the following is the preferable site for
bone marrow aspiration and biopsy in an adult?
A. Iliac crest
B. Sternum
C. Tibia
D. Spinous processes of a vertebra
A. Iliac crest
Explanation: 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 just beneath the skin, and neither blood vessels nor nerves are in the vicinity.
Mean cell volume (MCV) is calculated using the
following formula:
A. (Hgb ÷ RBC) × 10
B. (Hct ÷ RBC) × 10
C. (Hct ÷ Hgb) × 100
D. (Hgb ÷ RBC) × 100
B. (Hct ÷ RBC) × 10
What term describes the change in shape of erythrocytes seen on a Wright’s-stained peripheral
blood smear?
A. Poikilocytosis
B. Anisocytosis
C. Hypochromia
D. Polychromasia
A. Poikilocytosis
Explanation: Variation in shape of the erythrocytes on a peripheral blood smear is poikilocytosis. Anisocytosis refers to a change in size. Hypochromia is an increase in central pallor in erythrocytes. Polychromasia describes the bluish tinge of the immature erythrocytes (reticulocytes) circulating in the peripheral blood
Calculate the mean cell hemoglobin concentration (MCHC) using the following values:
Hgb: 15 g/dL (150 g/L)
Hct: 47 mL/dL (0.47)
RBC: 4.50 × 106/μL (4.50 × 1012/L)
A. 9.5% (.095)
B. 10.4% (.104)
C. 31.9% (.319)
D. 33.3% (.333)
C. 31.9% (.319)
Explanation: MCHC is the average concentration of Hgb in red cells 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 the Hct, and then multiplying by 100.
A decreased MCHC indicates that cells are hypochromic. In this example, (15 ÷ 47) × 100 = 31.9%. The reference range for MCHC is 32%–36%.
A manual white blood cell (WBC) count was performed. A total of 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 × 109/L
B. 2.5 × 109/L
C. 4.0 × 109/L
D. 8.0 × 109/L
A. 0.4 × 109/L
Explanation: The formula used for calculating manual cell counts
using a hemacytometer is: Number of cells counted × dilution factor × depth factor (10) divided by the area. In this example, 36 × 10 × 10 = 3600 ÷ 9 =
400/mm3 or 0.4 × 109/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. Siderocyte
explanation: Siderocytes are red cells 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. Hemoglobin (Hgb)
C. Hct
D. WBC count
C. Hct
explanation: Excessive anticoagulant causes shrinkage of cells; thus, the 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 red cells were counted in an area of 0.2 mm2. What is the RBC count?
A. 1.68 × 1012/L
B. 3.36 × 1012/L
C. 4.47 × 1012/L
D. 6.66 × 1012/L
B. 3.36 × 1012/L
Explanation:
RBC count = number of cells counted × dilution factor × depth factor (10), divided by the area.
In this example, 336 × 200 × 10 = 672,000 ÷ 0.2 = 3.36 × 106/mm3 = 3.36 × 1012/L.
What phagocytic cells produce lysozymes that are bacteriocidal?
A. Eosinophils
B. Lymphocytes
C. Platelets
D. Neutrophils
D. Neutrophils
If a patient has a reticulocyte count of 7% and an Hct of 20%, what is the corrected reticulocyte count?
A. 1.4%
B. 3.1%
C. 3.5%
D. 14%
B. 3.1%
Explanation: 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, 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
C. Hemolytic disease of the newborn
D. Acquired hemolytic anemia
A. Sickle cell anemia
What effect would using a buffer at pH 6.0 have on a Wright’s-stained smear?
A. Red cells would be stained too pink
B. White cell cytoplasm would be stained too blue
C. Red cells would be stained too blue
D. Red cells would lyse on the slide
A. Red cells would be stained too pink
Explanation: The pH of the buffer is critical in Romanowsky stains. When the pH is too low (<6.4), the red cells 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’s-stained blood smear?
A. Basophilic stippling
B. Heinz bodies
C. Howell–Jolly bodies
D. Siderotic granules
B. Heinz bodies
Explanation: Heinz bodies are irregular, refractile, purple inclusions that are not visible with Wright’s stain but show up
with supravital staining. The other three inclusions can be detected with Wright’s stain.
A falsely elevated Hct is obtained. Which of the following calculated values will not be affected?
A. MCV
B. MCH
C. MCHC
D. Red cell distribution width (RDW)
B. MCH
A Miller disk is an ocular device used to facilitate counting of:
A. Platelets
B. Reticulocytes
C. Sickle cells
D. Nucleated red blood cells (NRBCs)
B. Reticulocytes
SITUATION: RBC indices obtained on an anemic patient are as follows: MCV 88 μm3 (fL); MCH 30 pg; MCHC 34% (.340). The RBCs on the peripheral smear would appear:
A. Microcytic, hypochromic
B. Microcytic, normochromic
C. Normocytic, normochromic
D. Normocytic, hypochromic
C. 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. Blood drawn into a sodium citrate tube
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. Supravital staining
The Coulter principle for counting of cells is based upon 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. Isotonic solutions conduct electricity better than cells do
A correction is necessary for WBC counts when nucleated RBCs are seen on the peripheral smear because:
A. The WBC count would be falsely lower
B. The RBC count is too low
C. Nucleated RBCs are counted as leukocytes
D. Nucleated RBCs are confused with giant platelets
C. Nucleated RBCs are counted as leukocytes
Using an electronic cell counter analyzer, an increased RDW should correlate with:
A. Spherocytosis
B. Anisocytosis
C. Leukocytosis
D. Presence of NRBCs
B. Anisocytosis
Given the following values, which set of red blood cell 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. MCV 80 μm3 MCH 36.5 pg MCHC 39.0%
Which of the following statistical terms reflects the best index of precision when comparing two CBC parameters?
A. Mean
B. Median
C. Coefficient of variation
D. Standard deviation
C. Coefficient of variation
Which of the following is considered a normal hemoglobin?
A. Carboxyhemoglobin
B. Methemoglobin
C. Sulfhemoglobin
D. Deoxyhemoglobin
D. Deoxyhemoglobin
Which condition will shift the oxyhemoglobin dissociation curve to the right?
A. Acidosis
B. Alkalosis
C. Multiple blood transfusions
D. Increased quantities of hemoglobin S or C
A. Acidosis
What is the major type of leukocyte seen in the peripheral smear of a patient with aplastic anemia?
A. Segmented neutrophil
B. Lymphocyte
C. Monocyte
D. Eosinophil
B. Lymphocyte
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. 20%–44%
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. 6 months–2 years
Which of the following results on an automated differential suggests that a peripheral smear should be reviewed manually?
A. Segs = 70%
B. Band = 6%
C. Mono = 15%
D. Eos = 2%
C. Mono = 15%
Which is the first stage of erythrocytic maturation in which the cytoplasm is pink due to the formation of hemoglobin?
A. Reticulocyte
B. Pronormoblast
C. Basophilic normoblast
D. Polychromatic normoblast
D. Polychromatic normoblast
Which of the following can shift the hemoglobin oxygen dissociation curve to the right?
A. Increases in 2,3 DPG
B. Acidosis
C. Hypoxia
D. All of these options
D. All of these options
Which of the following Hgb configurations is characteristic of Hgb H?
A. γ4
B. α2-γ2
C. β4
D. α2-β2
A. γ4
Autoagglutination of red cells at room temperature can cause which of the following abnormal test results?
A. Low RBC count
B. High MCV
C. Low hematocrit
D. All of these options
D. All of these options
Hypersplenism is characterized by:
A. Polycythemia
B. Pancytosis
C. Leukopenia
D. Myelodysplasia
C. Leukopenia
Which of the following organs is responsible for the “pitting process” for RBCs?
A. Liver
B. Spleen
C. Kidney
D. Lymph nodes
B. Spleen
Spherocytes differ from normal red cells 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. Increased deformability
Which of the following is not associated with hereditary spherocytosis?
A. Increased osmotic fragility
B. An MCHC greater than 36%
C. Intravascular hemolysis
D. Extravascular hemolysis
C. Intravascular hemolysis
Which of the following disorders has an increase in osmotic fragility?
A. Iron deficiency anemia
B. Hereditary elliptocytosis
C. Hereditary stomatocytosis
D. Hereditary spherocytosis
D. Hereditary spherocytosis
The anemia seen in sickle cell disease is usually:
A. Microcytic, normochromic
B. Microcytic, hypochromic
C. Normocytic, normochromic
D. Normocytic, hypochromic
C. Normocytic, normochromic
Which is the major Hgb found in the RBCs of patients with sickle cell trait?
A. Hgb S
B. Hgb F
C. Hgb A2
D. Hgb A
D. Hgb A
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. Valine is substituted for glutamic acid at the sixth position of the β-chain
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. Fast mobility of Hgb C at pH 8.6
Which of the following hemoglobins 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. Hgb C
Which of the following electrophoretic results is consistent with a diagnosis of 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. Hgb A: 60% Hgb S: 40% Hgb A2: 2%
Explanation: Electrophoresis at alkaline pH usually shows 50%–70% Hgb A, 20%–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. Sickle cell disease
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. It is a rare acquired stem cell disorder that results in hemolysis
Hemolytic uremic syndrome (HUS) is
characterized by all of the following except:
A. Hemorrhage
B. Thrombocytopenia
C. Hemoglobinuria
D. Reticulocytopenia
D. Reticulocytopenia
An autohemolysis test is positive in all the following conditions except:
A. Glucose-6-phosphate dehydrogenase (G6PD) deficiency
B. Hereditary spherocytosis (HS)
C. Pyruvate kinase (PK) deficiency
D. Paroxysmal nocturnal hemoglobinuria (PNH)
D. Paroxysmal nocturnal hemoglobinuria (PNH)
Explanation: The autohemolysis test 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.
Which antibody is associated with paroxysmal cold hemoglobinuria (PCH)?
A. Anti-I
B. Anti-i
C. Anti-M
D. Anti-P
D. Anti-P
Explanation: PCH is caused by the anti-P antibody, a cold autoantibody that binds to the patient’s RBCs at low temperatures and fixes complement.
All of the following are associated with
intravascular hemolysis except:
A. Methemoglobinemia
B. Hemoglobinuria
C. Hemoglobinemia
D. Decreased haptoglobin
A. Methemoglobinemia
Autoimmune hemolytic anemia is best
characterized by which of the following?
A. Increased levels of plasma C3
B. Spherocytic red cells
C. Decreased osmotic fragility
D. Decreased unconjugated bilirubin
B. Spherocytic red cells
Explanation:
Spherocytes are characteristic of autoimmune hemolytic anemia and result in an increased osmotic fragility. In autoimmune hemolytic anemias (AIHAs),
production of autoantibodies against one’s own red cells causes hemolysis or phagocytic destruction of RBCs.
“Bite cells” are usually seen in patients with:
A. Rh null trait
B. Chronic granulomatous disease
C. G6PD deficiency
D. PK deficiency
C. G6PD deficiency
Explanation:
In patients with G6PD deficiency, the red cells are unable to reduce nicotinamide adenine dinucleotide phosphate (NADP) to NADPH; consequently, Hgb is denatured and Heinz bodies are formed. “Bite cells”
appear in the peripheral circulation as a result ofsplenic pitting of Heinz bodies.
The morphological classification of anemias is based on which of the following?
A. M:E (myeloid:erythroid) ratio
B. Prussian blue stain
C. RBC indices
D. Reticulocyte count
C. RBC indices
Which of the following is a common finding in aplastic anemia?
A. A monoclonal disorder
B. Tumor infiltration
C. Peripheral blood pancytopenia
D. Defective DNA synthesis
C. Peripheral blood pancytopenia
Explanation:
Aplastic anemia has many causes, such as chemical, drug, or radiation poisoning; congenital aplasia; and Fanconi’s 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. Bizarre multinucleated erythroblasts
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 nucleated RBCs
D. Schistocytes and nucleated RBCs
Which antibiotic(s) is (are) most often implicated in the development of aplastic anemia?
A. Sulfonamides
B. Penicillin
C. Tetracycline
D. Chloramphenicol
D. Chloramphenicol
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. Hereditary, intracorpuscular RBC defects
Which of the following conditions may produce spherocytes in a peripheral smear?
A. Pelger–Huët anomaly
B. Pernicious anemia
C. Autoimmune hemolytic anemia
D. Sideroblastic anemia
C. Autoimmune hemolytic anemia
A patient’s peripheral smear reveals numerous
NRBCs, marked variation of red cell morphology, and pronounced polychromasia. In addition to a
decreased Hgb and decreased Hct values, what other CBC parameters may be anticipated?
A. Reduced platelets
B. Increased MCHC
C. Increased MCV
D. Decreased red-cell distribution width (RDW)
C. Increased MCV
What red cell inclusion may be seen in the peripheral blood smear of a patient
postsplenectomy?
A. Toxic granulation
B. Howell–Jolly bodies
C. Malarial parasites
D. Siderotic granules
B. Howell–Jolly bodies
Reticulocytosis usually indicates:
A. Response to inflammation
B. Neoplastic process
C. Aplastic anemia
D. Red cell regeneration
D. Red cell regeneration