PEBC Diagnostic Procedures 3 — Questions and Answers
Question 1: A patient with type 2 diabetes has an HbA1c of 8.9%. What does this value most accurately reflect?
- Average blood glucose over the past 2 weeks
- Average blood glucose over the past 2–3 months (Correct answer)
- Fasting plasma glucose on the day of the test
- Postprandial glucose peaks over the past month
Correct answer: Average blood glucose over the past 2–3 months
HbA1c reflects glycosylated hemoglobin accumulated over the 2–3 month lifespan of red blood cells, providing an average blood glucose estimate.
Question 2: A patient's ABG shows pH 7.28, PaCO2 28 mmHg, HCO3 13 mEq/L. What is the primary acid-base disorder?
- Respiratory acidosis with metabolic compensation
- Metabolic alkalosis with respiratory compensation
- Metabolic acidosis with respiratory compensation (Correct answer)
- Mixed respiratory and metabolic acidosis
Correct answer: Metabolic acidosis with respiratory compensation
Low pH and low HCO3 indicate metabolic acidosis; the low PaCO2 reflects appropriate respiratory compensation (hyperventilation).
Question 3: Which serum marker is most specific for acute myocardial infarction?
- Lactate dehydrogenase (LDH)
- Myoglobin
- Creatine kinase-MB (CK-MB)
- Troponin I or T (Correct answer)
Correct answer: Troponin I or T
Cardiac troponins (I and T) are the most sensitive and specific biomarkers for myocardial injury and are the gold standard for diagnosing AMI.
Question 4: A pharmacist notes a patient's TSH is 0.08 mIU/L and free T4 is elevated. Which condition does this pattern suggest?
- Primary hypothyroidism
- Secondary hypothyroidism
- Subclinical hyperthyroidism
- Primary hyperthyroidism (overt) (Correct answer)
Correct answer: Primary hyperthyroidism (overt)
Suppressed TSH combined with elevated free T4 is diagnostic of overt primary hyperthyroidism, indicating excess thyroid hormone production.
Question 5: A urine culture grows >100,000 CFU/mL of E. coli with sensitivity to nitrofurantoin. A pregnant patient at 36 weeks asks if this antibiotic is safe. The pharmacist should advise:
- Nitrofurantoin is safe at any gestational age
- Nitrofurantoin should be avoided near term due to risk of neonatal hemolytic anemia (Correct answer)
- Nitrofurantoin is contraindicated throughout pregnancy
- Nitrofurantoin is the preferred first-line agent in the third trimester
Correct answer: Nitrofurantoin should be avoided near term due to risk of neonatal hemolytic anemia
Nitrofurantoin is generally safe in the first and second trimesters but is contraindicated at ≥36 weeks gestation due to the risk of neonatal hemolytic anemia.
Question 6: Which diagnostic test is used to confirm celiac disease after a positive anti-tissue transglutaminase IgA (tTG-IgA) antibody screen?
- Colonoscopy with random biopsies
- Esophagogastroduodenoscopy (EGD) with small bowel biopsy (Correct answer)
- Capsule endoscopy
- Hydrogen breath test
Correct answer: Esophagogastroduodenoscopy (EGD) with small bowel biopsy
Duodenal/small bowel biopsy via EGD is required to confirm celiac disease by demonstrating villous atrophy and crypt hyperplasia.
Question 7: A patient on vancomycin therapy has a trough level of 22 mg/L. The target trough range is 15–20 mg/L. What is the most appropriate action?
- Increase the dose to ensure adequate coverage
- Continue current dosing and recheck in 72 hours
- Reduce the dose or extend the dosing interval and recheck levels (Correct answer)
- Switch to oral vancomycin immediately
Correct answer: Reduce the dose or extend the dosing interval and recheck levels
A supratherapeutic trough suggests accumulation risk; reducing the dose or extending the interval with repeat monitoring is appropriate to avoid nephrotoxicity.
PEBC Diagnostic Procedures 3
A patient with type 2 diabetes has an HbA1c of 8.9%.
What does this value most accurately reflect?