MLPAO Hematology and Coagulation Advanced Practice

Question 1

What is the significance of Auer rods found on a peripheral blood smear?

Accepted Answer

They are pathognomonic for acute myeloid leukemia

Answer

Auer rods are needle-shaped, reddish-purple crystalline inclusions found in the cytoplasm of myeloid blast cells. They are pathognomonic (uniquely diagnostic) for acute myeloid leukemia and are never seen in acute lymphoblastic leukemia or benign conditions. Multiple Auer rods (faggot cells) are characteristic of acute promyelocytic leukemia (APL/M3).

Question 2

Which hematological malignancy is associated with the Philadelphia chromosome t(9;22)?

Accepted Answer

Chronic myeloid leukemia (CML)

Answer

The Philadelphia chromosome results from a translocation between chromosomes 9 and 22, creating the BCR-ABL1 fusion gene. This is the hallmark of chronic myeloid leukemia (CML) and is present in over 95% of CML cases. It is also found in some cases of ALL. Tyrosine kinase inhibitors (imatinib) target this abnormality.

Question 3

What is the principle of flow cytometry immunophenotyping in hematological malignancies?

Accepted Answer

Identifying cell surface and intracellular markers using fluorescent-labeled antibodies

Answer

Flow cytometry identifies cell types by using fluorescent-labeled monoclonal antibodies that bind to specific CD (cluster of differentiation) markers on cell surfaces or within cells. Cells pass through a laser beam in single file, and fluorescence patterns identify lineage (myeloid vs. lymphoid) and maturation stage.

Question 4

Which condition is characterized by a markedly elevated white blood cell count with a predominance of mature lymphocytes in an elderly patient?

Accepted Answer

Chronic lymphocytic leukemia (CLL)

Answer

Chronic lymphocytic leukemia (CLL) is the most common leukemia in adults in Canada, typically presenting in patients over 60 years. It is characterized by a persistent lymphocytosis of mature-appearing small lymphocytes. Smudge cells (damaged fragile CLL cells) are characteristically seen on the blood smear.

Question 5

What is heparin-induced thrombocytopenia (HIT) type II?

Accepted Answer

An immune-mediated condition causing platelet activation, thrombocytopenia, and paradoxical thrombosis

Answer

HIT type II is a serious immune-mediated condition where antibodies against heparin-platelet factor 4 (PF4) complexes activate platelets, causing both thrombocytopenia (platelet count drop >50%) and a paradoxical prothrombotic state. It typically occurs 5-14 days after heparin exposure and requires immediate heparin cessation and alternative anticoagulation.

MLPAO - Medical Laboratory Professionals Association of Ontario Practice Test

MLPAO - Medical Laboratory Professionals Association of Ontario Practice Test

MLPAO Hematology and Coagulation Advanced Practice