CMT Hematology & Coagulation 2

Question 1

Schistocytes on a peripheral smear with thrombocytopenia are most suggestive of which condition?

Accepted Answer

Thrombotic thrombocytopenic purpura

Answer

TTP is a microangiopathic hemolytic anemia in which RBCs are sheared by microthrombi, producing schistocytes.

Question 2

Coarse basophilic stippling in RBCs is classically associated with which condition?

Accepted Answer

Lead poisoning

Answer

Lead inhibits pyrimidine 5'-nucleotidase, leaving aggregated ribosomal RNA visible as coarse stippling.

Question 3

A specimen has an MCHC of 39 g/dL and RBC agglutination on the smear. What is the most appropriate corrective action?

Accepted Answer

Warm the specimen to 37°C and rerun

Answer

Cold agglutinins falsely elevate MCV and MCHC and falsely lower RBC count; warming to 37°C disperses the agglutinates.

Question 4

Which stain is used to perform a manual reticulocyte count?

Accepted Answer

New methylene blue

Answer

New methylene blue is a supravital stain that precipitates residual RNA in reticulocytes.

Question 5

Heinz bodies seen with crystal violet supravital stain are most characteristic of which disorder after oxidant drug exposure?

Accepted Answer

G6PD deficiency

Answer

G6PD-deficient cells cannot protect hemoglobin from oxidation, so denatured hemoglobin precipitates as Heinz bodies.

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