MLS HEMATOLOGY EXAM 2023-2024 /HEMATOLOGY MLS ACTUAL EXAM 400 QUESTIONS AND CORRECT DETAILED ANSWERS WITH RATIONALES (VERIFIED ANSWERS) |ALREADY GRADED A+

MLS HEMATOLOGY EXAM 2023-2024 /HEMATOLOGY MLS

ACTUAL EXAM 400 QUESTIONS AND CORRECT DETAILED

ANSWERS WITH RATIONALES (VERIFIED ANSWERS)

|ALREADY GRADED A+

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 - ANSWER- b.

Rationale: 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. RDW - ANSWER- b.

Rationale: the MCH = Hb x 10/RBC count and is not affected by the Hct. The

MCV = Hct x 10/RBC count, and MCHC - Hb x 100/Hct; therefore, an erroneous

Hct will affect these parameters. Centrifugal force for microhematocrit

determination should be 12,000 g for 5 min in order to avoid error caused by

trapped plasma. The red cell distribution width (RDW) is calculated by electronic

cell counters and reflects the variance in the size of the red cell population.

Electronic cell counters calculate Hct from the MCV and RBC count. Therefore,

the RDW would be affected by an erroneous MCV

a Miller disk is an ocular device used to facilitate counting of:

a. platelets

b. reticulocytes

c. sickle cells

d. NRBCs - ANSWER- b.

Rationale: 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 red cells are

counted in the smaller one

RBC indicies obtained on an anemic patient are as follows: MCV 88 um3 (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 - ANSWER- c.

Rationale: the 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 Hb. Therefore, the anemia is normocytic normochromic

All of the following factors may influence the erythrocyte sedimentation rate

(ESR) except:

a. blood drawn into a sodium citrate tube

b. anisocytosis, poikilocytosis

c. plasma proteins

d. caliber of the tube - ANSWER- a.

Rationale: 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 different

caliber tubes

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- b.

Rationale: the reticulum within the reticulocytes consists of RNA, which cannot

be stained with Wright's stain. Supravital staining with new methylene blue is used

to identify the reticulocytes

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 - ANSWER- a.

Rationale: electronic cell (Coulter) counters use the principle of electrical

impedance. Two electrodes suspended in isotonic solutions are separated by a glass

tube having a small aperture. A vacuum is applied, and as a cell passes through the

aperture it impedes the flow of current and generates a voltage pulse

A correction is necessary for WBC counts when 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 - ANSWER- c.

Rationale: the automated hematology analyzers enumerate all nucleated cells.

NRBCs are counted along with WBCs, falsely elevating the WBC count. To

correct the WBC count, determine the number of NRBCs per 100 WBCs.

Corrected WBC count = (uncorrected WBC count / [NRBCs + 100]) x 100

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

a. spherocytosis

b. anisocytosis

c. leukocytosis

d. presence of NRBCs - ANSWER- b.

Rationale: the RDW parameter correlates with the degree of anisocytosis seen on

the morphological examination. The RR is 11.5-14.5%

Given the following values, which set of RBC indices suggests spherocytosis?

a. MCV 76 MCH 19.9 MCHC 28.5%

b. MCV 90 MCH 30.5 MCHC 32.5%

c. MCV 80 MCH 36.5 MCHC 39.0%

d. MCV 81 MCH 29 MCHC 34.8% - ANSWER- c.

Rationale: spherocytes have a decreased cell diameter and volume, which results

in loss of central pallor and discoid shape. The index most affected is the MCHC,

usually being in excess of 36%

Which of the following statistical terms reflects the best index of precision when

comparing two CBC parameters?

a. mean