AOA Clinical Diagnosis and Laboratory Medicine

Question 1

A 55-year-old man presents with fatigue, pallor, and a mean corpuscular volume (MCV) of 110 fL. Which finding would best confirm megaloblastic anemia?

Accepted Answer

Hypersegmented neutrophils on peripheral smear

Answer

Target cells on peripheral smear

Answer

Elevated serum ferritin

Answer

Decreased reticulocyte count

Question 2

Which laboratory finding is most characteristic of disseminated intravascular coagulation (DIC)?

Accepted Answer

Elevated D-dimer with prolonged PT and PTT

Answer

Elevated fibrinogen with normal PT

Answer

Isolated thrombocytopenia with normal PT

Answer

Decreased D-dimer with elevated fibrinogen

Question 3

A patient with suspected myocardial infarction presents 6 hours after symptom onset. Which biomarker is most sensitive and specific at this time point?

Accepted Answer

Troponin I

Answer

Myoglobin

Answer

CK-MB

Answer

LDH

Question 4

An anion gap of 22 mEq/L is found in a patient with altered mental status. Which condition is the LEAST likely cause of this elevated anion gap?

Accepted Answer

Hyperchloremic metabolic acidosis

Answer

Diabetic ketoacidosis

Answer

Lactic acidosis

Answer

Uremia

Question 5

Which test is considered the gold standard for diagnosing iron deficiency anemia?

Accepted Answer

Bone marrow iron staining

Answer

Serum ferritin

Answer

Serum iron level

Answer

Total iron-binding capacity (TIBC)

Question 6

A 30-year-old woman has a serum calcium of 11.5 mg/dL. PTH is elevated. What is the most likely diagnosis?

Accepted Answer

Primary hyperparathyroidism

Answer

Malignancy-associated hypercalcemia

Answer

Milk-alkali syndrome

Answer

Vitamin D toxicity

Question 7

Which urinalysis finding is most consistent with a diagnosis of nephrotic syndrome?

Accepted Answer

Fatty casts and oval fat bodies

Answer

WBC casts

Answer

RBC casts

Answer

Granular muddy-brown casts