PEBC Diagnostic Procedures 2 — Questions and Answers
Question 1: A patient's serum creatinine is 180 µmol/L and eGFR is 28 mL/min/1.73m². Which CKD stage does this represent?
- Stage 2 (mild decrease)
- Stage 3b (moderately severe decrease)
- Stage 4 (severe decrease) (Correct answer)
- Stage 5 (kidney failure)
Correct answer: Stage 4 (severe decrease)
An eGFR of 15–29 mL/min/1.73m² corresponds to CKD Stage 4 (severe decrease in kidney function).
Question 2: Which laboratory finding is most consistent with iron-deficiency anemia?
- Elevated serum ferritin, low TIBC
- Low serum ferritin, elevated TIBC (Correct answer)
- Low serum ferritin, low TIBC
- Elevated serum ferritin, elevated TIBC
Correct answer: Low serum ferritin, elevated TIBC
Iron-deficiency anemia is characterized by low serum ferritin (depleted stores) and elevated TIBC (transferrin unsaturated).
Question 3: A pharmacist reviews a patient's ECG and notes a prolonged QTc of 510 ms. Which drug interaction is most likely responsible?
- Metformin + lisinopril
- Azithromycin + haloperidol (Correct answer)
- Atorvastatin + amlodipine
- Pantoprazole + metoprolol
Correct answer: Azithromycin + haloperidol
Both azithromycin and haloperidol independently prolong the QTc interval, and their combination significantly increases the risk of torsades de pointes.
Question 4: A patient's urine dipstick shows 3+ protein and 2+ blood. The most appropriate next diagnostic step is:
- Repeat dipstick in 1 week
- Urine microscopy and ACR (albumin-to-creatinine ratio) (Correct answer)
- Serum electrolytes only
- Renal ultrasound alone
Correct answer: Urine microscopy and ACR (albumin-to-creatinine ratio)
Persistent proteinuria and hematuria on dipstick require urine microscopy and ACR to quantify proteinuria and evaluate for glomerular pathology.
Question 5: Which INR range is the therapeutic target for a patient with a mechanical heart valve receiving warfarin?
- 1.5–2.0
- 2.0–3.0
- 2.5–3.5 (Correct answer)
- 3.5–4.5
Correct answer: 2.5–3.5
Mechanical heart valves generally require a higher INR target of 2.5–3.5 to prevent thromboembolism.
Question 6: A fasting lipid panel shows LDL-C 4.8 mmol/L, HDL-C 0.9 mmol/L, and TG 3.2 mmol/L. Which calculated value is unreliable?
- Total cholesterol
- LDL-C via Friedewald equation (Correct answer)
- Non-HDL cholesterol
- HDL-C
Correct answer: LDL-C via Friedewald equation
The Friedewald equation (LDL-C = TC − HDL − TG/2.2) is inaccurate when triglycerides exceed 4.5 mmol/L, but is also less reliable at TG > 2.3 mmol/L; direct LDL measurement should be used when TG are elevated.
Question 7: Which test is used to diagnose H. pylori infection in a patient currently taking a proton pump inhibitor?
- Urea breath test immediately
- Serology (IgG antibody test)
- Stool antigen test after 2-week PPI washout (Correct answer)
- Gastric biopsy urease test while on PPI
Correct answer: Stool antigen test after 2-week PPI washout
PPIs suppress H. pylori activity and cause false-negative urea breath and stool antigen tests; a 2-week PPI washout before stool antigen testing improves accuracy.
PEBC Diagnostic Procedures 2
A patient's serum creatinine is 180 µmol/L and eGFR is 28 mL/min/1.73m².
Which CKD stage does this represent?