AOA Clinical Diagnosis and Laboratory Medicine 2

Question 1

Which interpretation of an arterial blood gas — pH 7.28, PaCO2 55 mmHg, HCO3 24 mEq/L — is correct?

Accepted Answer

Respiratory acidosis

Answer

Metabolic acidosis

Answer

Respiratory alkalosis

Answer

Mixed metabolic and respiratory acidosis

Question 2

A patient has an AST/ALT ratio greater than 2:1 with elevated GGT and elevated MCV. What is the most likely diagnosis?

Accepted Answer

Alcoholic liver disease

Answer

Viral hepatitis B

Answer

Autoimmune hepatitis

Answer

Non-alcoholic fatty liver disease

Question 3

In interpreting a Coombs test for hemolytic anemia, a positive direct antiglobulin test (DAT) indicates:

Accepted Answer

Antibodies bound directly to the patient's red blood cells

Answer

Antibodies in the serum against foreign red cells

Answer

Complement activation only in plasma

Answer

Alloantibody production after transfusion

Question 4

A 45-year-old with dyslipidemia has an LDL of 190 mg/dL despite lifestyle changes. According to ACC/AHA guidelines, which lab result would most support initiating high-intensity statin therapy?

Accepted Answer

LDL ≥ 190 mg/dL on two separate measurements

Answer

HDL of 60 mg/dL

Answer

Triglycerides of 150 mg/dL

Answer

CRP of 1.0 mg/L

Question 5

Which thyroid function test pattern is consistent with subclinical hypothyroidism?

Accepted Answer

Elevated TSH, normal free T4

Answer

Low TSH, low free T4

Answer

Normal TSH, low free T4

Answer

Elevated TSH, elevated free T4

Question 6

A patient has a serum sodium of 125 mEq/L with low urine osmolality (< 100 mOsm/kg) and low urine sodium (< 20 mEq/L). What is the most likely cause?

Accepted Answer

Primary polydipsia

Answer

SIADH

Answer

Adrenal insufficiency

Answer

Hypothyroidism

Question 7

Which finding on peripheral blood smear is most consistent with thrombotic thrombocytopenic purpura (TTP)?

Accepted Answer

Schistocytes (helmet cells)

Answer

Spherocytes

Answer

Hypersegmented neutrophils

Answer

Teardrop cells