MLPAO Hematology and Coagulation Case Studies

Question 1

A patient has hemoglobin 85 g/L, MCV 65 fL, RDW 18%, and serum ferritin 5 µg/L. What is the most likely diagnosis?

Accepted Answer

Iron deficiency anemia

Answer

The combination of low hemoglobin, microcytosis (MCV 65 fL), elevated RDW (anisocytosis), and very low ferritin (5 µg/L) is classic for iron deficiency anemia. Beta-thalassemia trait typically has a normal RDW and normal ferritin. The low ferritin is the most specific finding for iron deficiency.

Question 2

A 70-year-old patient has WBC 85 × 10⁹/L with 90% mature lymphocytes and numerous smudge cells. What is the most likely diagnosis?

Accepted Answer

Chronic lymphocytic leukemia

Answer

The clinical picture of an elderly patient with markedly elevated WBC, predominance of mature lymphocytes, and smudge cells (basket cells) is classic for chronic lymphocytic leukemia (CLL). Smudge cells result from the fragility of CLL lymphocytes during smear preparation. Immunophenotyping would show CD5+, CD19+, CD23+ B cells.

Question 3

A patient on warfarin has an INR of 8.5 with no active bleeding. What is the recommended management?

Accepted Answer

Hold warfarin and administer oral vitamin K

Answer

For an INR >4.5-10 without significant bleeding, the recommended approach is to hold warfarin and administer low-dose oral vitamin K (1-2.5 mg). This will lower the INR within 24-48 hours. Fresh frozen plasma or prothrombin complex concentrate is reserved for active life-threatening bleeding.

Question 4

A patient has prolonged PT and aPTT that both correct on mixing with normal plasma. Which condition is most likely?

Accepted Answer

Multiple factor deficiency (such as liver disease or DIC)

Answer

When both PT and aPTT are prolonged and correct on mixing, it indicates deficiency of one or more coagulation factors in both pathways. Common causes include liver disease (decreased synthesis), DIC (consumption), and vitamin K deficiency. Inhibitors would not correct on mixing study.

Question 5

A newborn has hemoglobin F 90%, hemoglobin A 0%, and hemoglobin A2 2%. What is the most likely diagnosis?

Accepted Answer

Either normal newborn or beta-thalassemia major — requires follow-up

Answer

At birth, hemoglobin F normally comprises 60-90% of total hemoglobin, and HbA gradually increases. The absence of HbA could be normal in early neonatal life or could indicate beta-thalassemia major. Follow-up hemoglobin electrophoresis at 6-12 months is essential when HbF to HbA switching should be complete.

MLPAO - Medical Laboratory Professionals Association of Ontario Practice Test

MLPAO - Medical Laboratory Professionals Association of Ontario Practice Test

MLPAO Hematology and Coagulation Case Studies