AANPCB AANPCB Diagnostic Testing and Interpretation 1 — Questions and Answers
Question 1: A patient's TSH is elevated at 8.2 mIU/L with a low free T4. Which diagnosis does this pattern most indicate?
- Hyperthyroidism
- Primary hypothyroidism (Correct answer)
- Secondary hypothyroidism
- Subclinical hyperthyroidism
Correct answer: Primary hypothyroidism
Elevated TSH with low free T4 is the classic pattern of primary hypothyroidism, where the pituitary compensates for insufficient thyroid hormone by secreting more TSH.
Question 2: Which finding on urinalysis is most specific for a urinary tract infection?
- Hematuria
- Proteinuria
- Nitrites and leukocyte esterase (Correct answer)
- Elevated specific gravity
Correct answer: Nitrites and leukocyte esterase
Nitrites indicate bacterial conversion of urinary nitrates (suggesting gram-negative organisms), while leukocyte esterase indicates pyuria; together they are highly specific for UTI.
Question 3: A patient's HbA1c is 7.2%. What does this result indicate about their average blood glucose over the past 2–3 months?
- Normal glycemic control below diabetic threshold
- Above the ADA goal of less than 7% for most adults with diabetes (Correct answer)
- Critically elevated requiring emergency intervention
- Consistent with prediabetes, not diabetes
Correct answer: Above the ADA goal of less than 7% for most adults with diabetes
An HbA1c of 7.2% confirms diabetes and exceeds the ADA's general target of less than 7%, indicating the need to optimize glucose management.
Question 4: Which electrocardiographic finding is most diagnostic of an acute ST-elevation myocardial infarction (STEMI)?
- T-wave inversion in precordial leads
- New ST-segment elevation in two or more contiguous leads (Correct answer)
- Prolonged QT interval
- Right bundle branch block
Correct answer: New ST-segment elevation in two or more contiguous leads
New ST-segment elevation of ≥1 mm in two or more contiguous leads represents acute transmural myocardial ischemia and is the hallmark ECG finding requiring immediate reperfusion therapy.
Question 5: What does a positive D-dimer result primarily indicate when evaluating a patient for pulmonary embolism?
- Confirms the diagnosis of pulmonary embolism
- Indicates fibrin breakdown, suggesting active clot formation or thrombus (Correct answer)
- Rules out deep vein thrombosis
- Confirms aortic dissection
Correct answer: Indicates fibrin breakdown, suggesting active clot formation or thrombus
D-dimer is a fibrin degradation product elevated whenever clot is present, but it is nonspecific; a positive result indicates possible thrombus and warrants imaging, not a definitive PE diagnosis.
Question 6: A patient has a fasting blood glucose of 118 mg/dL. According to ADA criteria, how is this classified?
- Normal
- Prediabetes (impaired fasting glucose) (Correct answer)
- Diabetes mellitus
- Hypoglycemia
Correct answer: Prediabetes (impaired fasting glucose)
ADA defines prediabetes as a fasting glucose of 100–125 mg/dL; a value of 118 mg/dL falls within this range, indicating impaired fasting glucose requiring lifestyle intervention.
AANPCB AANPCB Diagnostic Testing and Interpretation 1
A patient's TSH is elevated at 8.2 mIU/L with a low free T4.
Which diagnosis does this pattern most indicate?