Heme 1.1 Basic Hematology Concepts and Laboratory Procedures

Question 1

1. 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

Answer 1

A. A false increase in hematocrit (Hct) value

Question 2

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

Answer 2

A. Anisocytosis

Question 3

3. 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

Answer 3

A. Iliac crest

Question 4

4. 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

Answer 4

B. (Hct ÷ RBC) × 10

Question 5

5. 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

Answer 5

A. Poikilocytosis

Question 6

6. 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)

Answer 6

C. 31.9% (0.319)

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%.

Question 7

7. A manual white blood cell (WBC) count was performed. In total 36 cells were counted in all 9-mm^2 squares of a Neubauer-ruled hemacytometer. A 1:10 dilution was used. What is the WBC count?

A. 0.4 × 10^9/L
B. 2.5 × 10^9/L
C. 4.0 × 10^9/L
D. 8.0 × 10^9/L

Answer 7

A. 0.4 × 10^9/L

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/mm^3 or 0.4 × 10^9/L.

Question 8

8. When an erythrocyte containing iron granules is stained with Prussian blue, the cell is called a:

A. Spherocyte
B. Leptocyte
C. Schistocyte
D. Siderocyte

Answer 8

D. Siderocyte

Question 9

9. 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

Answer 9

C. Hct

Excessive anticoagulant causes shrinkage of cells; thus, Hct will be affected. RBC and WBC counts remain the same, as does the Hgb content.

Question 10

10. A 1:200 dilution of a patient’s sample was made, and 336 RBCs were counted in an area of 0.2 mm2. What is the RBC count?

A. 1.68 × 10^12/L
B. 3.36 × 10^12/L
C. 4.47 × 10^12/L
D. 6.66 × 10^12/L

Answer 10

B. 3.36 × 10^12/L

RBC count = number of cells counted × dilution factor × depth factor (10), ÷ area.
In this example, 336 × 200 × 10 = 672,000 ÷ 0.2 = 3.36 × 10^6/mm3 = 3.36 × 10^12/L.

Question 11

11. What phagocytic cells produce lysozymes that are bacteriocidal?

A. Eosinophils
B. Lymphocytes
C. Platelets (PLTs)
D. Neutrophils

Answer 11

D. Neutrophils

Question 12

12. 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%

Answer 12

B. 3.1%

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.

Question 13

13. 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

Answer 13

A. Sickle cell anemia

Question 14

14. 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

Answer 14

A. RBCs would be stained too pink

Question 15

15. 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

Answer 15

B. Heinz bodies

Question 16

16. 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)

Answer 16

B. Mean corpuscular hemoglobin (MCH)

Question 17

17. 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)

Answer 17

B. Reticulocytes

Question 18

18. 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

Answer 18

C. Normocytic, normochromic

Question 19

19. 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

Answer 19

A. Blood drawn into a sodium citrate tube

Question 20

20. What staining method is used most frequently to stain and manually count reticulocytes?

A. Immunofluorescence
B. Supravital staining
C. Romanowsky staining
D. Cytochemical staining

Answer 20

B. Supravital staining

Question 21

21. 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

Answer 21

A. Isotonic solutions conduct electricity better than cells do

Question 22

22. 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

Answer 22

C. NRBCs are counted as leukocytes

Question 23

23. Using an electronic cell counter analyzer, an increased RDW should correlate with:

A. Spherocytosis
B. Anisocytosis
C. Leukocytosis
D. Presence of NRBCs

Answer 23

B. Anisocytosis

Question 24

24. 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%

Answer 24

C. MCV 80 μm3 MCH 36.5 pg MCHC 39.0%

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%.

Question 25

25. 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

Answer 25

C. Coefficient of variation

Question 26

26. Which of the following is considered a normal Hgb? A. Carboxyhemoglobin B. Methemoglobin C. Sulfhemoglobin D. Deoxyhemoglobin

Answer 26

D. Deoxyhemoglobin 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.

Question 27

27. 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

Answer 27

A. Acidosis

Question 28

28. 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

Answer 28

B. Lymphocyte 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.

Question 29

29. 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%

Answer 29

C. 20%–44%

Question 30

30. 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

Answer 30

A. 6 months–2 years

Question 31

31. 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%

Answer 31

C. Mono = 15% 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.

Question 32

32. 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

Answer 32

D. Polychromatic normoblast

Question 33

33. 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

Answer 33

D. All of these options

Question 34

34. Which of the following Hgb configurations is characteristic of Hgb H? A. γ4 B. α2-γ2 C. β4 D. α2-β2

Answer 34

C. β4 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.

Question 35

35. 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

Answer 35

D. All of these options