Robert R. Harr Archives - Exam Reviewer

Medical Laboratory Science Reviewer: Qualitative and Quantitative White Blood Cell Disorders

examreviewer — Tue, 28 Nov 2023 23:52:08 +0000

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
Hematology/Evaluate laboratory data to recognize health and disease states/Infectious
mononucleosis/2
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
Hematology/Evaluate laboratory data to recognize health and disease
states/HIV/Microscopic morphology/1
Which inclusions may be seen in leukocytes?
A. Döhle bodies
B. Basophilic stippling
C. Malarial parasites
D. Howell–Jolly bodies
Hematology/Apply knowledge of fundamental characteristics/WBC inclusions/1
Which of the following is contained in the primary granules of the neutrophil?
A. Lactoferrin
B. Myeloperoxidase
C. Histamine
D. Alkaline phosphatase
Hematology/Apply knowledge of fundamental biological characteristics/WBC kinetics/2
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%
Hematology/Evaluate laboratory data to recognize health and disease states/Differential
normal values/2
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
Hematology/Apply knowledge of fundamental biological characteristics/WBC microscopic
morphology/2
Neutropenia is present in patients with which absolute neutrophil count?
A. Less than 1.5 × 109/L
B. Less than 5.0 × 109/L
C. Less than 10.0 × 109/L
D. Less than 15.0 × 109/L
Hematology/Evaluate laboratory data to recognize health and disease states/Differential
normal values/2
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
Hematology/Recognize morphological changes associated with diseases/WBC inclusions/2
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
Hematology/Recognize morphological changes associated with diseases/WBC inclusions/2
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
Hematology/Evaluate laboratory data to recognize health and disease states/Differentials/2
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
Hematology/Apply knowledge of fundamental biological characteristics/WBC kinetics/2
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
Hematology/Recognize morphological changes associated with diseases/WBC morphology/2

Answers key

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.
C HIV infection brings about several hematological abnormalities seen on peripheral
blood smear examination; most patients demonstrate reactive lymphocytes and have
granulocytopenia.
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.
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.
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.
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.
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 × 109/L.
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.
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.
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.
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.
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.

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Medical Laboratory Science Reviewer: Macrocytic and Normochromic Anemias

examreviewer — Tue, 28 Nov 2023 22:54:25 +0000

Which morphological classification is characteristic of megaloblastic anemia?
A. Normocytic, normochromic
B. Microcytic, normochromic
C. Macrocytic, hypochromic
D. Macrocytic, normochromic
Hematology/Correlate clinical and laboratory data/Microscopic morphology/RBCs/2
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
Hematology/Evaluate laboratory data to recognize health and disease states/2
All of the following are characteristics of megaloblastic anemia except:
A. Pancytopenia
B. Elevated reticulocyte count
C. Hypersegmented neutrophils
D. Macrocytic erythrocyte indices
Hematology/Correlate clinical and laboratory data/Anemia/Megaloblastic/2
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
Hematology/Select course of action/Anemia/Therapy/3
Which of the following disorders is associated with ineffective erythropoiesis?
A. G6PD deficiency
B. Liver disease
C. Hgb C disease
D. Megaloblastic anemia
Hematology/Evaluate laboratory data to recognize health and disease states/RBC
physiology/2
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 × 1012/L; WBC = 12,500/μL (12.5 × 109/L); PLT = 250,000/μL (250 × 109/L)
B. RBC = 4.5 × 1012/L; WBC = 6,500/μL (6.5 × 109/L); PLT = 150,000/μL (150 × 109/L)
C. RBC = 3.0 × 1012/L; WBC = 5,000/μL (5.0 × 109/L); PLT = 750,000/μL (750 × 109/L)
D. RBC = 2.5 × 1012/L; WBC = 2,500/μL (2.5 × 109/L); PLT = 50,000/μL (50 × 109/L)
Hematology/Correlate clinical and laboratory data/Anemias/2
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
Hematology/Apply principles of basic laboratory procedures/Microscopic morphology/2
The macrocytes typically seen in megaloblastic processes are:
A. Crescent shaped
B. Teardrop shaped
C. Oval shaped
D. Pencil shaped
Hematology/Apply principles of basic laboratory procedures/Microscopic
morphology/Differentials/2
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%
Hematology/Correlate clinical and laboratory data/Megaloblastic anemia/2
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
Hematology/Correlate clinical and laboratory data/Megaloblastic anemia/2

Answers key

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.
D Pernicious anemia is caused by lack of intrinsic factor, which prevents vitamin B12
absorption.
B Megaloblastic anemias are associated with ineffective erythropoiesis and, therefore, a
decrease in the reticulocyte count.
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.
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.
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.
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.
C Macrocytes in true megaloblastic conditions are oval, as opposed to the round shape of
macrocytes usually seen in alcoholism and obstructive liver disease.
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.
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.

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Medical Laboratory Science Reviewer: Hypochromic and Microcytic Anemias

examreviewer — Tue, 28 Nov 2023 22:17:33 +0000

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
Hematology/Correlate clinical and laboratory data/Microscopic morphology/Osmotic
fragility/1
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
Hematology/Correlate clinical and laboratory data/Anemia/Iron deficiency/2
IDA may be distinguished from anemia of chronic infection by:
A. Serum iron level
B. RBC morphology
C. RBC indices
D. TIBC
Hematology/Evaluate laboratory data to recognize health and disease states/Anemia/3
Which anemia has RBC morphology similar to that seen in IDA?
A. Sickle cell anemia
B. Thalassemia syndrome
C. Pernicious anemia
D. HS
Hematology/Correlate laboratory data with other laboratory data to assess test
results/Anemia/RBC microscopic morphology/2
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
Hematology/Evaluate laboratory data to recognize health and disease states/Anemia/Iron
deficiency/2
Storage iron is usually best determined by:
A. Serum transferrin levels
B. Hgb values
C. Myoglobin values
D. Serum ferritin levels
Hematology/Apply knowledge of basic laboratory procedures/Iron/1
All of the following are associated with sideroblastic anemia except:
A. Increased serum iron
B. Ringed sideroblasts
C. Hypochromic anemia
D. Decreased serum ferritin
Hematology/Evaluate laboratory data to recognize health and disease
states/Anemia/Sideroblastic/2
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
Hematology/Apply knowledge of fundamental biological
characteristics/Hemoglobinopathy/1
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
Hematology/Correlate clinical and laboratory diseases/Hemoglobin/Hemoglobinopathy/2
A patient has an Hct of 30%, an Hgb of 8 g/dL, and a RBC count of 4.0 × 1012/L. What
is the morphological classification of this anemia?
A. Normocytic, normochromic
B. Macrocytic, hypochromic
C. Microcytic, hypochromic
D. Normocytic, hyperchromic
Hematology/Evaluate laboratory data to recognize health and disease
states/Hemoglobinopathy/Characteristics/3
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
Hematology/Correlate laboratory results with disease states/2
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
Hematology/Correlate laboratory data to recognize health and disease states/2

Answers key

B Osmotic fragility is decreased because numerous target cells are present and have
increased surface volume in patients with thalassemia major.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.

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Medical Laboratory Science Reviewer: Normocytic and Normochromic Anemias

examreviewer — Tue, 28 Nov 2023 21:51:26 +0000

Hypersplenism is characterized by:
A. Polycythemia
B. Pancytosis
C. Leukopenia
D. Myelodysplasia
Hematology/Correlate clinical and laboratory data/WBCs/Hypersplenism/2
Which of the following organs is responsible for the “pitting process” in RBCs?
A. Liver
B. Spleen
C. Kidney
D. Lymph nodes
Hematology/Apply knowledge of fundamental biological characteristics/Physiology/1
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
Hematology/Apply knowledge of fundamental biological characteristics/RBC microscopic
morphology/2
Which of the following is not associated with HS?
A. Increased osmotic fragility
B. MCHC greater than 36%
C. Intravascular hemolysis
D. Extravascular hemolysis
Hematology/Correlate clinical and laboratory data/Hereditary spherocytosis/2
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)
Hematology/Evaluate laboratory data to recognize health and disease states/Special
tests/Osmotic fragility/2
The anemia seen in sickle cell disease is usually:
A. Microcytic, normochromic
B. Microcytic, hypochromic
C. Normocytic, normochromic
D. Normocytic, hypochromic
Hematology/Apply knowledge of fundamental biological characteristics/RBC microscopic
morphology/Hemoglobinopathy/1
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
Hematology/Apply knowledge of fundamental biological
characteristics/Anemia/Hemoglobinopathy/1
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
Hematology/Apply knowledge of fundamental biological
characteristics/Hemoglobinopathy/1
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
Hematology/Apply knowledge of fundamental biological
characteristics/Anemia/Hemoglobinopathy/1
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
Hematology/Correlate clinical and laboratory data/Hemoglobin electrophoresis/1
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%
Hematology/Evaluate laboratory data to recognize health and disease/Special
tests/Electrophoresis/2
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
Hematology/Apply knowledge of fundamental biological
characteristics/Anemia/Hemoglobinopathy/1
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
Hematology/Apply knowledge of fundamental biological characteristics/PNH/1
Hemolytic uremic syndrome (HUS) is characterized by all of the following except:
A. Hemorrhage
B. Thrombocytopenia
C. Hemoglobinuria
D. Reticulocytopenia
Hematology/Correlate clinical and laboratory data/HUS/2
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
Hematology/Correlate clinical and laboratory tests/Special tests/2
Which antibody is associated with paroxysmal cold hemoglobinuria (PCH)?
A. Anti-I
B. Anti-i
C. Anti-M
D. Anti-P
Hematology/Apply knowledge of fundamental biological characteristics/Anemia/PCH/1
All of the following are associated with intravascular hemolysis except:
A. Methemoglobinemia
B. Hemoglobinuria
C. Hemoglobinemia
D. Decreased haptoglobin
Hematology/Correlate clinical and laboratory data/Anemia/Hemolytic/2
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
Hematology/Correlate clinical and laboratory data/Anemia/Hemolytic/2
“Bite cells” are usually seen in patients with:
A. Rh null trait
B. Chronic granulomatous disease
C. G6PD deficiency
D. PK deficiency
Hematology/Correlate clinical and laboratory data/RBC microscopic morphology/1
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
Hematology/Correlate clinical and laboratory diseases/RBC microscopic morphology/1
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
Hematology/Apply knowledge of fundamental biological characteristics/Aplastic anemia/1
Congenital dyserythropoietic anemias (CDAs) are characterized by:
A. Bizarre multinucleated erythroblasts
B. Cytogenetic disorders
C. Megaloblastic erythropoiesis
D. An elevated M:E ratio
Hematology/Apply knowledge of fundamental biological
characteristics/Anemia/Characteristics/2
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
Hematology/Correlate clinical and laboratory data/RBC microscopic morphology/Anemia/2
Which antibiotic(s) is (are) most often implicated in the development of aplastic
anemia?
A. Sulfonamides
B. Penicillin
C. Tetracycline
D. Chloramphenicol
Hematology/Correlate clinical and laboratory data/Aplastic anemia/1
Sickle cell disorders are:
A. Hereditary, intracorpuscular RBC defects
B. Hereditary, extracorpuscular RBC defects
C. Acquired, intracorpuscular RBC defects
D. Acquired, extracorpuscular RBC defects
Hematology/Apply knowledge of fundamental biological concepts/2
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
Hematology/Evaluate laboratory data to recognize health and disease states/Morphology/2
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
Hematology/Correlate lab data with clinical picture/Complete blood counts/3
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
Hematology/Correlate clinical laboratory data/Inclusions/1
Reticulocytosis usually indicates:
A. Response to inflammation
B. Neoplastic process
C. Aplastic anemia
D. RBC regeneration
Hematology/Correlate laboratory data for clinical conditions/Morphology/2
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
Hematology/Evaluate laboratory data to recognize health and disease states/Red cell
membrane/2

Answers key

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.
B The spleen is the supreme filter of the body, pitting imperfections from the erythrocyte
without destroying the integrity of the membrane.
D Spherocytes lose their deformability because of a defect in spectrin, a membrane
protein, and are therefore prone to splenic sequestration and 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.
D Spherocytic cells have decreased tolerance to swelling and, therefore, hemolyse at a
higher concentration of sodium salt compared with normal RBCs.
C Sickle cell disease is a chronic hemolytic anemia classified as a normocytic,
normochromic anemia.
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.
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.
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.
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.
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.
D Autosplenectomy occurs in sickle cell anemia as a result of repeated infarcts to the
spleen caused by an overwhelming sickling phenomenon.
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.
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.
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.
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.
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.
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.
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.
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.
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.
A There are four classifications of CDAs, each characterized by ineffective
erythropoiesis, increased unconjugated bilirubin, and bizarre multinucleated erythroid
precursors.
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.
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.
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.
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.
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.
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.
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.
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 post Medical Laboratory Science Reviewer: Normocytic and Normochromic Anemias appeared first on Exam Reviewer.

Medical Laboratory Science Reviewer: Basic Hematology Concepts and Laboratory Procedures

examreviewer — Tue, 28 Nov 2023 21:26:35 +0000

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
Hematology/Apply principles of basic laboratory procedures/Microscopic
morphology/Differential/2
Variation in red blood cell (RBC) size observed on the peripheral blood smear is
described as:
A. Anisocytosis
B. Hypochromia
C. Poikilocytosis
D. Pleocytosis
Hematology/Apply knowledge of fundamental biological characteristics/Microscopic
morphology/RBCs/1
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
Hematology/Apply knowledge of fundamental biological characteristics/Bone marrow/1
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
Hematology/Calculate/RBC indices/2
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
Hematology/Apply knowledge of fundamental biological characteristics/Microscopic
morphology/RBCs/1
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 × 106/µL (4.50 × 1012/L)
A. 9.5% (0.095)
B. 10.4% (0.104)
C. 31.9% (0.319)
D. 33.3% (0.333)
Hematology/Calculate/RBC indices/2
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 × 109/L
B. 2.5 × 109/L
C. 4.0 × 109/L
D. 8.0 × 109/L
Hematology/Calculate/Manual WBCs/2
When an erythrocyte containing iron granules is stained with Prussian blue, the cell is
called a:
A. Spherocyte
B. Leptocyte
C. Schistocyte
D. Siderocyte
Hematology/Apply knowledge of fundamental biological characteristics/RBCs microscopic
morphology/Stain/1
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
Hematology/Apply knowledge to identify sources of error/Specimen collection and
handling/CBC/3
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 × 1012/L
B. 3.36 × 1012/L
C. 4.47 × 1012/L
D. 6.66 × 1012/L
Hematology/Calculate/Manual RBCs/2
What phagocytic cells produce lysozymes that are bacteriocidal?
A. Eosinophils
B. Lymphocytes
C. Platelets (PLTs)
D. Neutrophils
Hematology/Apply knowledge of fundamental biological characteristics/Leukocytes/1
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%
Hematology/Apply principles of basic laboratory procedures/Calculate/Reticulocytes/2
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
Hematology/Apply principles of basic laboratory procedures/RBCs/Osmotic fragility/2
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
Hematology/Evaluate laboratory data to recognize problems/Microscopic
morphology/Stains/2
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
Hematology/Apply principles of basic laboratory procedures/Microscopic morphology/RBC
inclusions/2
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) Hematology/Evaluate sources of
error/Microhematocrit/3
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)
Hematology/Apply knowledge of standard operating procedures/Manual counts/1
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
Hematology/Evaluate laboratory data to recognize health and disease states/RBC indices/2
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
Hematology/Apply principles of basic laboratory procedures/ESRs/2
What staining method is used most frequently to stain and manually count
reticulocytes?
A. Immunofluorescence
B. Supravital staining
C. Romanowsky staining
D. Cytochemical staining
Hematology/Apply knowledge of standard operating procedures/Reticulocytes/1
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
Hematology/Apply principles of basic laboratory procedures/Instrumentation/Cell counters/2
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
Hematology/Evaluate laboratory data to take corrective action according to predetermined
criteria/Leukocytes/2
Using an electronic cell counter analyzer, an increased RDW should correlate with:
A. Spherocytosis
B. Anisocytosis
C. Leukocytosis
D. Presence of NRBCs
Hematology/Correlate laboratory data with other laboratory data to assess test results/RBC
microscopic morphology/2
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%
Hematology/Evaluate laboratory data to recognize health and disease states/RBC indices/3
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
Hematology/Correlate laboratory data with other laboratory data to assess test
results/QC/Statistics/2
Which of the following is considered a normal Hgb?
A. Carboxyhemoglobin
B. Methemoglobin
C. Sulfhemoglobin
D. Deoxyhemoglobin
Hematology/Apply knowledge of fundamental biological characteristics/Hemoglobin/1
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
Hematology/Correlate laboratory data with other laboratory data to assess test
results/RBCs/Metabolism/2
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
Hematology/Correlate clinical and laboratory data/Leukocytes/Aplastic anemia/1
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%
Hematology/Correlate basic laboratory values/Differentials/1
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
Hematology/Evaluate laboratory data/Differentials/2
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%
Hematology/Correlate laboratory data/Instrumentation/2
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
Hematology/Apply knowledge of fundamental biological characteristics/Microscopic
morphology/1
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
Hematology/Evaluate laboratory data to recognize health and disease states/O2 dissociation
curves/2
Which of the following Hgb configurations is characteristic of Hgb H?
A. γ4
B. α2-γ2
C. β4
D. α2-β2
Hematology/Apply knowledge of fundamental biological characteristics/Hemoglobin/2
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
Hematology/Correlate laboratory data with other laboratory data to assess test
results/CBCs/3

Answers key

A Insufficient centrifugation does not pack down RBCs; therefore, the Hct, which is the
volume of packed cells, will increase.
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.
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.
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).
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.
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 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 × 109/L.
D Siderocytes are RBCs containing iron granules and are visible when stained with
Prussian blue.
C Excessive anticoagulant causes shrinkage of cells; thus, Hct will be affected. RBC and
WBC counts remain the same, as does the Hgb content.
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 × 106/mm3 = 3.36 × 1012/L.
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.
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 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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
B The RDW parameter correlates with the degree of anisocytosis seen on the
morphological examination. The reference range is 11.5% to 14.5%.
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%.
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 (e.g., WBC and
RBC counts or low vs. high controls).
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.
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.
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.
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.
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).
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.
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.
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.
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.
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.

The post Medical Laboratory Science Reviewer: Basic Hematology Concepts and Laboratory Procedures appeared first on Exam Reviewer.