Medical Laboratory Technician Exam FREE Medical Laboratory Technician Hematology and Coagulation Questions and Answers 3

Question 1

In a patient with suspected heparin-induced thrombocytopenia (HIT), which laboratory finding supports the diagnosis?

Accepted Answer

Positive serotonin release assay

Answer

The serotonin release assay is the gold standard confirmatory test for HIT, detecting platelet-activating antibodies against heparin-PF4 complexes.

Question 2

Which hemoglobin electrophoresis pattern is characteristic of sickle cell trait (HbAS)?

Accepted Answer

HbA greater than HbS with normal HbA2

Answer

In sickle cell trait, HbA predominates (approximately 55-60%) over HbS (approximately 35-40%) with normal HbA2 levels.

Question 3

A mixing study corrects a prolonged aPTT. What does this result indicate?

Accepted Answer

Factor deficiency

Answer

Correction of a prolonged aPTT in a mixing study indicates a factor deficiency because the normal plasma supplies the missing factor.

Question 4

Which cell type is the primary precursor of platelets in the bone marrow?

Accepted Answer

Megakaryocyte

Answer

Megakaryocytes are large bone marrow cells that shed cytoplasmic fragments to produce platelets.

Question 5

An INR of 4.5 in a patient on warfarin therapy indicates which of the following?

Accepted Answer

Excessive anticoagulation requiring dose adjustment

Answer

An INR of 4.5 exceeds the typical therapeutic range of 2.0-3.0 and indicates excessive anticoagulation with increased bleeding risk.

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