CBC, Peripheral Smear, Reticulocyte count, RBC indices, CRP, ESR, Blood Cell morphology Flashcards
is the process by which the formed elements of blood
are produced
Hematopoiesis
In the bone marrow, the first morphologically recognizable erythroid precursor is the
pronormoblast. This cell can undergo four to five cell divisions, which result in the production of 16–32 mature red
cells.
The mature red cell size
8 μm in diameter, anucleate, discoid in shape, and extremely pliable in order to traverse the microcirculation successfully; its membrane integrity
is maintained by the intracellular generation of ATP.
Normal red cell production results in the daily replacement of 0.8–1% of all circulating red cells in the body, since the average red cell lives 100–120 days. The organ responsible for red cell production is called the erythron.
The erythron is a dynamic organ made up of a rapidly proliferating pool of
marrow erythroid precursor cells and a large mass of mature circulating red blood cells.
The physiologic regulator of red cell production, the glycoprotein hormone
EPO, is produced and released by peritubular capillary lining cells within the kidney
A small amount of EPO is produced by hepatocytes. The fundamental stimulus for EPO production is the availability of O2 for tissue metabolic needs
Key to EPO gene regulation is
hypoxia-inducible factor (HIF)-1α. In the presence of O2, HIF-1α is hydroxylated at a key proline, allowing HIF-1α to be ubiquitinated and degraded via the proteasome
pathway.
EPO level
the normal level being 10–25 U/L. When the hemoglobin concentration falls below
100–120 g/L (10–12 g/dL), plasma EPO levels increase in proportion to the severity of the anemia (Fig. 77-2).
In circulation, EPO has a half-clearance time of 6–9 h. EPO acts by binding to specific receptors
on the surface of marrow erythroid precursors, inducing them to proliferate and to mature
With EPO stimulation, red cell production can increase four- to fivefold within a 1- to 2-week period, but only in the presence of adequate nutrients, especially iron.
mean hematocrit value for adult males and females is
47% (standard deviation, ±7%) and that for
adult females is 42% (±5%).
Any single hematocrit or hemoglobin value carries with it a likelihood of associated anemia.
Thus, a hematocrit of <39% in an adult male or <35% in an adult female has only about a 25% chance of being normal. Hematocrit levels are less useful than hemoglobin levels in assessing anemia because they are calculated rather than measured directly
(WHO) defines anemia as a
hemoglobin level <130 g/L (13 g/dL) in men and <120 g/L (12 g/dL) in women
If blood loss is mild, enhanced O2 delivery is achieved through changes in the O2–hemoglobin dissociation
curve mediated by a decreased pH or increased CO2
(Bohr effect).
With acute blood loss, hypovolemia dominates the clinical picture, and the hematocrit and hemoglobin levels do not reflect the volume of blood lost.
Signs of vascular instability appear with acute losses of 10–15% of the total blood volume.
% of the blood volume is lost suddenly, patients are unable to compensate with the usual mechanisms of vascular contraction and changes in regional blood flow. The patient prefers to remain supine and will
show postural hypotension and tachycardia
> 30
(i.e., >2 L in the average-sized adult), signs of hypovolemic shock including confusion, dyspnea, diaphoresis, hypotension, and tachycardia appear
> 40%
Intravascular hemolysis with release of free hemoglobin may be associated
with acute back pain, free hemoglobin in the plasma and urine, and renal failure.
because of the intrinsic compensatory
mechanisms that govern the O2–hemoglobin dissociation curve, the gradual onset of anemia—particularly in young patients—may not be associated with signs or symptoms until the anemia is
severe
hemoglobin <70–80 g/L [7–8 g/dL]
With chronic anemia, intracellular levels of ___ rise, shifting the dissociation curve to the right and facilitating O2 unloading. This compensatory
mechanism can only maintain normal tissue O2 delivery in the face of a 20–30 g/L (2–3 g/dL) deficit in hemoglobin concentration
2,3-bisphosphoglycerate
Chronic inflammatory states (e.g., infection, rheumatoid arthritis, cancer) areassociated with
mild to moderate anemia
whereas lymphoproliferative
disorders, such as chronic lymphocytic leukemia and certain other B cell neoplasms, may be associated with
autoimmune hemolysis
The skin and mucous membranes may be pale if the
hemoglobin is
<80–100 g/L (8–10 g/dL).
If the palmar creases are lighter in color than the surrounding skin when the hand is hyperextended, the hemoglobin level is usually <80 g/L (8 g/dL).
High-normal hemoglobin values may be
seen in men and women who live at altitude or smoke heavily.
Hemoglobin elevations due to smoking reflect
normal compensation due to the displacement of O2 by CO in hemoglobin binding
TIBC; an indirect measure of
serum transferrin),
Microcytosis is reflected by a lower than normal MCV
(<80), whereas high values (>100) reflect macrocytosis
The MCH and MCHC reflect defects in hemoglobin synthesis (hypochromia)
Mean cell volume (MCV) =
(hematocrit × 10)/(red cell
count × 10^6)
90 ± 8 fL
Mean cell hemoglobin (MCH) =
(hemoglobin × 10)/(red
cell count × 10^6)
30 ± 3 pg
Mean cell hemoglobin concentration =
(hemoglobin × 10)/hematocrit, or MCH/MCV
33 ± 2%
As a complement to the red cell indices, the blood smear also reveals variations in cell size (anisocytosis) and shape (poikilocytosis).
Poikilocytosis suggests a defect
in the maturation of red cell precursors in the bone marrow or
fragmentation of circulating red cells. The blood smear may also
reveal polychromasia—red cells that are slightly larger than normal
and grayish blue in color on the Wright-Giemsa stain. These cells
are reticulocytes that have been prematurely released from the bone
marrow,
In the absence of a functional
spleen, nuclear remnants are not culled from the red cells and remain as small homogeneously staining blue inclusions on Wright stain
Howell-Jolly bodies.
Red cells may become fragmented
in the presence of foreign bodies in the circulation, such as mechanical heart valves, or in the setting of thermal injury
Red cell fragmentation.
Red cell changes in . The left panel
shows a teardrop-shaped cell.
myelofibrosis
The red cells in uremia may acquire numerous
regularly spaced, small, spiny projections. Such cells, called burr cells or echinocytes, are readily distinguishable from irregularly spiculated acanthocytes
Uremia.
Spur cells are recognized as distorted red
cells containing several irregularly distributed thornlike projections.
Cells with this morphologic abnormality are also called
acanthocytes.
This residual RNA is metabolized over the first 24–36 h of the reticulocyte’s life span in circulation. Normally, the reticulocyte count ranges from
1 to 2% and reflects the daily replacement of 0.8–1.0% of the circulating red cell population.
if the EPO and erythroid marrow responses to moderate anemia [hemoglobin <100 g/L (10 g/dL)] are intact, the red cell production rate increases to two to three times normal within
10 days following the onset of anemia
Correction #1 for Anemia:
This correction produces the corrected reticulocyte count.
In a person whose reticulocyte count is 9%, hemoglobin 7.5 g/dL, and hematocrit 23%, the absolute reticulocyte count = 9 × (7.5/15) [or × (23/45)] = 4.5%
Note. This correction is not done if the reticulocyte count is reported in absolute numbers (e.g., 50,000/μL of blood)
Correction #2 for Longer Life of Prematurely Released Reticulocytes in the Blood
This correction produces the reticulocyte production index.
In a person whose reticulocyte count is 9%, hemoglobin 7.5 gm/dL, and hematocrit 23%, the reticulocyte production index
9x
(7.5/15)(hemoglobin correction)/ 2( maturation time concentration)
= 2.25
Erythroid cells take
∼4.5 days to mature.
The normal serum iron ranges
from 9 to 27 μmol/L (50–150 μg/dL), whereas the
normal TIBC is 54–64 μmol/L (300–360 μg/dL); the normal transferrin saturation ranges from 25 to 50%. A diurnal variation in the serum iron leads to a variation in the percent transferrin saturation.
Adult males have serum ferritin levels that average
∼100 μg/L, corresponding to iron stores of ∼1 g.
Adult females have lower serum ferritin levels averaging 30 μg/L, reflecting lower iron stores (∼300 mg). A serum ferritin level of 10–15 μg/L indicates depletion of body iron stores
ferritin is also an acute-phase reactant and, in the presence of acute or chronic inflammation, may rise several-fold above baseline levels.
As a rule, a serum ferritin >
200 μg/L means there is at least some iron in tissue stores
A patient with a hypoproliferative anemia and a
reticulocyte production index <2 will demonstrate an M/E ratio of 2 or 3:1.
In contrast, patients with hemolytic disease and a
Reticulocyte production index >3 will have an M/E ratio of at least 1:1
Erythroid hyperplasia. This marrow shows an
increase in the fraction of cells in the erythroid lineage as might be seen when a normal marrow compensates for acute blood loss or hemolysis. The myeloid/erythroid (M/E) ratio is about 1:1.
Myeloid hyperplasia. This marrow shows an increase
in the fraction of cells in the myeloid or granulocytic lineage as might be seen in a normal marrow responding to infection. The myeloid/ erythroid (M/E) ratio is >3:1
On carefully prepared bone marrow smears, small ferritin granules can normally be seen under oil immersion in 20–40% of developing erythroblasts. Such cells are called
sideroblasts
Normal Bone Marrow cells
Note that the nucleated cellular elements account
for ∼40–50% and the fat (clear areas) accounts for ∼50–60% of the area.
a reticulocyte production index >2.5 indicates that
hemolysis is most likely
A reticulocyte production index <2 indicates either a hypoproliferative anemia or maturation disorder.
% of all cases of anemia are hypoproliferative in nature
At least 75%
Polycythemia
Concern that the hemoglobin level may be abnormally high is usually triggered at 170 g/L (17 g/dL) for men and 150 g/L (15 g/dL) for women
Anemias associated with normocytic and normochromic red cells and an inappropriately low reticulocyte response (reticulocyte index <2–2.5) are
hypoproliferative anemias
Normally 80% of iron passing through the plasma transferrin pool is recycled from senescent red
cells.
Absorption of approximately
1 mg/d is required from the diet in men, and 1.4 mg/d in women to maintain homeostasis. As long as transferrin saturation is maintained between 20 and 60% and erythropoiesis is not increased, use of iron stores is not required
Normally, the iron bound to transferrin turns over 6–8 times per day. Assuming a normal plasma iron level of 80–100 μg/dL, the amount of iron passing
through the transferrin pool is 20–24 mg/d.
Normal blood leukocyte counts are
4.3–10.8 × 109/L, with
neutrophils 45–74% bands 0–4%, lymphocytes 16–45% monocytes 4–10% eosinophils 0–7% basophils 0–2%.
WBC morphology
MYELOBLAST- Prominent
nucleoli
PROMYELOCYTE-Large cell Primary granules
appear
MYELOCYTE- Secondary granules appear
METAMYELOCYTE- Kidney bean– shaped nucleus
NEUTROPHIL-Condensed, multilobed nucleus
The primary granules contain hydrolases, elastase,
myeloperoxidase, cathepsin G, cationic proteins, and bactericidal/ permeability-increasing protein, which is important for killing gram-negative bacteria.
Azurophil granules also contain defensins, a family of cysteine-rich polypeptides with broad antimicrobial activity against bacteria, fungi, and certain enveloped viruses.
Secondary granule
contents are readily released extracellularly, and their mobilization is important in modulating inflammation
severe acute bacterial infection, prominent neutrophil cytoplasmic granules, called
toxic granulations, are occasionally seen. Toxic granulations are immature or abnormally staining azurophil granules
Cytoplasmic inclusions, also called
Döhle bodies can be seen during infection and are fragments of ribosome-rich endoplasmic reticulum.
Döhle bodies are discrete, blue-staining, nongranular areas found in the periphery of the cytoplasm of the neutrophil in infections and other toxic states
In this benign disorder, the
majority of granulocytes are bilobed. The nucleus frequently has a spectacle-like, or “pince-nez,” configuration.
Pelger-Hüet anomaly
The best place to examine blood cell morphology is the
feathered edge of the blood smear where red cells lie in a single layer, side by side, just barely touching one another but not overlapping
The platelets are usually ___ diameter
1–2 μm in diameter and have a blue granulated appearance. There is usually 1 platelet for every 20 or red cells
Large platelets may be a sign of rapid platelet turnover,
RBC size
One can gauge their size by comparing the red cell to the nucleus of a small lymphocyte.
Both are normally about 8 μm wide. Red cells that are smaller than the small lymphocyte nucleus may be microcytic; those larger than the small lymphocyte nucleus may be macrocytic.
Macrocytic cells also tend to be more oval than spherical in shape and are sometimes called macroovalocytes.
The automated mean corpuscular volume (MCV) can
assist in making a classification. However, some patients may have both iron and vitamin B12 deficiency, which will produce an MCV in the normal range but wide variation in red cell size
When the red cells vary greatly in size, anisocytosis is said to be present.
When the red cells vary greatly in shape, poikilocytosis is said to be present. The electronic cell counter provides an independent assessment of variability in red cell size.
It measures the range of red cell volumes and reports
the results as “red cell distribution width” (RDW) This value is calculated from the MCV; thus, cell width is not being measured but cell volume is
The width of the red cell volume distribution curve is what determines the RDW
The RDW is calculated as follows:
RDW = (standard deviation of MCV ÷ mean MCV) × 100.
In the presence of morphologic anisocytosis,
RDW (normally 11–14%) increases to 15–18%.
In patients with microcytic anemia, the differential diagnosis is generally between iron deficiency and thalassemia.
In thalassemia, the small red cells are generally of uniform size with a normal small RDW.
In iron deficiency, the size variability and
the RDW are large
a large RDW can suggest a dimorphic anemia when a chronic atrophic gastritis can produce both vitamin B12 malabsorption to produce macrocytic anemia and blood loss to produce iron deficiency. RDW also has been reported as a risk factor for all-cause mortality in
population-based studies
They are never “hyperchromic.” If more than the
normal amount of hemoglobin is made, the cells get larger—they donot become darker.
—diffuse fine or coarse blue dots in the red cell
usually representing RNA residue—especially common in lead poisoning
Basophilic stippling
—dense blue circular inclusions that represent
nuclear remnants—their presence implies defective splenic function
Howell-Jolly bodies
—red cells may be released or pushed out of the marrow prematurely before nuclear extrusion—often implies a myelophthisic process or a vigorous narrow response to anemia, usually hemolytic anemia
Nuclei
—the red cell cytoplasm has a bluish hue,
reflecting the persistence of ribosomes still actively making hemoglobin
in a young red cell
Polychromatophilia
Vital stains are necessary to see precipitated hemoglobin called
Heinz bodies.
Small red cells without the central
pallor are
spherocytes; they can be seen in hereditary spherocytosis, hemolytic anemias of other causes, and clostridial sepsis
____are teardrop-shaped cells that can be seen in hemolytic anemias, severe iron deficiency, thalassemias, myelofibrosis, and myelodysplastic syndromes.
Dacrocytes
A teardrop-shaped red blood cell (left panel) and a nucleated red blood cell (right panel) as typically seen with myelofibrosis and extramedullary hematopoiesis
___ helmet-shaped cells that reflect microangiopathic
hemolytic anemia or fragmentation on an artificial heart valve
Schistocytes
___ spiculated red cells with the spikes evenly spaced; they can represent an artifact of abnormal drying of the blood smear or reflect changes in stored blood. They also can be seen in renal failure
and malnutrition and are often reversible.
Echinocytes
Echinocytes are found in patients with severe uremia, in glycolytic red cell enzyme defects, and in microangiopathic hemolytic anemia.
are spiculated red cells with the spikes irregularly distributed. This process tends to be irreversible and reflects underlying renal disease, abetalipoproteinemia, or splenectomy
Acanthocytes
Acanthocytes are present in severe liver disease, in patients with abetalipoproteinemia, and in rare patients with McLeod blood group
are elliptical-shaped red cells that can reflect an inherited defect in the red cell membrane, but they also are seen in iron deficiency, myelodysplastic syndromes, megaloblastic anemia, and thalassemias
Elliptocytes
Elliptical shape of red cells is related to weakened membrane structure,
usually due to mutations in spectrin
___ are red cells in which the area of central pallor takes on the morphology of a slit instead of the usual round shape
Stomatocytes
Stomatocytes can indicate an inherited red cell membrane defect and also can be seen in alcoholism
This often is seen as an artifact in a dehydrated
blood smear. These cells can be seen in hemolytic anemias and in conditions in which the red cell is overhydrated or dehydrated
___have an area of central pallor that contains a dense center, or bull’s-eye
Target cells
These cells are seen classically in thalassemia, but they are also present in iron deficiency, cholestatic liver disease, and some hemoglobinopathies. They also can be generated artifactually by improper slide making
Small numbers of target cells are seen with liver disease and thalassemia. Larger numbers are typical of hemoglobin C disease
Some patients have red cell clumping (called
agglutination) in which the red cells pile upon one another; it is seen in certain paraproteinemias and autoimmune hemolytic anemias. Another abnormal distribution involves red cells lying in single cell rows on top of one another like stacks of coins.
This is called rouleaux formation and reflects abnormal serum protein levels.
___are generally the most abundant white cell. They are round, are 10–14 μm wide, and contain a lobulated nucleus with two to five lobes connected by a thin chromatin thread.
Neutrophils
Bands are immature neutrophils that have not completed nuclear condensation and have a U-shaped nucleus. Bands reflect a left shift in neutrophil maturation in an effort to make more cells more rapidly
Vacuolated neutrophils may be a sign of bacterial sepsis.
in WBC
The presence of 1- to 2-μm blue cytoplasmic inclusions, called
Döhle bodies, can reflect
infections, burns, or other inflammatory states.
If the neutrophil granules are larger than normal and stain a darker blue, “toxic granulations” are said to be present, and they also suggest a systemic inflammation
Döhle body. Neutrophil band with Döhle body. The
neutrophil with a sausage-shaped nucleus in the center of the field is a band form. Döhle bodies are discrete, blue-staining nongranular areas found in the periphery of the cytoplasm of the neutrophil in
infections and other toxic states. They represent aggregates of rough endoplasmic reticulum.
The presence of neutrophils with more than five nuclear lobes suggests
Megaloblastic anemia. Large misshapen granules may reflect the inherited Chédiak-Higashi syndrome
____are slightly larger than neutrophils, have bilobed nuclei, and contain large red granules.
Eosinophils
Diseases of eosinophils are associated
with too many of them rather than any morphologic or qualitative
change.
___are even rarer than eosinophils in the blood.
They have large dark blue granules and may be increased as part of chronic myeloid leukemia
Basophils
.
In the presence of viral infections, more of the lymphocytes are larger, about the size of neutrophils, with abundant cytoplasm and a less condensed nuclear chromatin. These cells are called
reactive lymphocytes
About 1% of lymphocytes are larger and contain blue granules in a light blue cytoplasm; they are called large granular lymphocytes.
chronic lymphoid leukemia, the
small lymphocytes are increased in number, and many of them are ruptured in making the blood smear, leaving a smudge of nuclear material without a surrounding cytoplasm or cell membrane; they are called
smudge cells and are rare in the absence of chronic lymphoid leukemia.
___are the largest white blood cells, ranging from 15 to 22μm in diameter. The nucleus can take on a variety of shapes but usually appears to be folded; the cytoplasm is gray
Monocytes
(multilobed polymorphonuclear leukocytes) are larger
than normal neutrophils with five or more segmented nuclear lobes.
Hypersegmented neutrophils
They are commonly seen with folic acid or vitamin B12 deficiency.
Spiculated red cells are of two types:
acanthocytes are contracted dense cells with irregular membrane projections that vary in length and width;
echinocytes have small, uniform,
and evenly spaced membrane projections
__together with a
marked increase in the platelet count, are seen in myeloproliferative
disorders,
Giant platelets,
especially primary thrombocythemia.
The percentage of the
space that consists of hematopoietic cells is referred to as
marrow cellularity. In adults, normal marrow cellularity is 35–40%.
If demands
for increased marrow production occur, cellularity may increase to meet the demand. As people age, the marrow cellularity decreases and the marrow fat increases.
Patients >70 years old may have a
20–30% marrow cellularity.
Marrow aspirate specimen with a myeloid/erythroid ratio (M/E ratio) of 1:1–2, typical for a patient with a hemolytic anemia or one recovering from
blood loss.
Erythroid hyperplasia of the marrow.
Marrow aspirate specimen showing a myeloid/erythroid ratio of ≥3:1, suggesting either a loss of red blood cell precursors or an expansion of myeloid elements.
Myeloid hyperplasia of the marrow.
An orthochromatic normoblast with a collar of blue granules (mitochondria encrusted with iron) surrounding
the nucleus.
Ringed sideroblast.
Note prominent
cytoplasmic granules in the leukemia cells.
Acute promyelocytic leukemia.
Peripheral blood smear showing
leukemia cells with typical “flower-shaped” nucleus
Adult T cell leukemia.
Lymphocytes with frequently
convoluted nuclei (Sézary cells) in a patient with advanced mycosis
fungoides.
Sézary’s syndrome.
A Reed-Sternberg cell is present
near the center of the field; a large cell with a bilobed nucleus and
prominent nucleoli giving an “owl’s eyes” appearance. The majority
of the cells are normal lymphocytes, neutrophils, and eosinophils that
form a pleiomorphic cellular infiltrate
Hodgkin’s disease.
Erythrocyte sedimentation rate
Females: 0–20 mm/h
Males: 0–15 mm/h
with low-grade fevers or
possible disease, the most valuable measurements are
the C-reactive protein level and the erythrocyte sedimentation rate. These markers of inflammatory processes are particularly helpful in detecting
occult disease.
Measurement of circulating IL-6 is useful because
IL-6 induces C-reactive protein
The erythrocyte sedimentation rate (ESR)
and the C-reactive protein (CRP) level are indirect and direct measures of the acute-phase response, respectively, these markers can be followed serially over time to monitor disease
It is noteworthy that the ESR changes relatively
slowly, and its measurement more often than weekly usually is not useful;
in contrast, CRP concentrations change rapidly, and daily measurements can be useful in the appropriate context.
An extremely elevated ESR (>100 mm/h) has a 90%
predictive value for a serious underlying disease (Table 144-3). Work is ongoing to identify other potentially useful inflammatory markers (e.g., procalcitonin, serum amyloid A protein);
Causes of an Extremely Elevated Erythrocyte
Sedimentati on Rate (>100 mm/h)
Infectious diseases (35–40)
Inflammatory diseases (15–20)
Malignancies (15–20)
Other (20–35)
