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

Low pH with elevated PaCO2 and normal bicarbonate indicates an acute respiratory acidosis without metabolic compensation.

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

An AST:ALT ratio >2:1, elevated GGT, and macrocytosis (elevated MCV) form a classic triad strongly suggesting alcoholic 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

The direct Coombs (DAT) detects antibodies or complement already bound to the patient's own red blood cells, indicating autoimmune or drug-induced hemolysis.

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

ACC/AHA guidelines recommend high-intensity statin therapy for LDL ≥190 mg/dL, regardless of 10-year cardiovascular risk score.

Question 5

Which thyroid function test pattern is consistent with subclinical hypothyroidism?

Accepted Answer

Elevated TSH, normal free T4

Answer

Subclinical hypothyroidism is defined by elevated TSH with a normal free T4, indicating early thyroid insufficiency without overt hormonal deficiency.

AOA - AOA Board Certified Practice Test

AOA - AOA Board Certified Practice Test

AOA Clinical Diagnosis and Laboratory Medicine 2