AANPCB AANPCB Diagnostic Testing and Interpretation 2 — Questions and Answers
Question 1: Which finding on a complete blood count (CBC) is most consistent with iron deficiency anemia?
- Elevated MCV with normal RDW
- Low MCV (microcytic) with elevated RDW and low ferritin (Correct answer)
- Elevated WBC with left shift
- Low platelet count with normal MCV
Correct answer: Low MCV (microcytic) with elevated RDW and low ferritin
Iron deficiency anemia presents with microcytic (low MCV) red cells of variable size (elevated RDW) due to uneven iron supply, with low ferritin confirming depleted iron stores.
Question 2: A chest X-ray shows a 'bat-wing' or 'butterfly' perihilar opacification pattern. Which condition does this most suggest?
- Lobar pneumonia
- Pulmonary edema (Correct answer)
- Pleural effusion
- Pneumothorax
Correct answer: Pulmonary edema
The bilateral perihilar 'bat-wing' opacity on CXR is characteristic of pulmonary edema, reflecting fluid accumulation in the alveoli and interstitium from elevated pulmonary venous pressure.
Question 3: Which serum marker is most specific for acute myocardial infarction when interpreting cardiac biomarkers?
- CK-MB
- Troponin I or T (Correct answer)
- LDH
- Myoglobin
Correct answer: Troponin I or T
Cardiac-specific troponin I and T are the most sensitive and specific biomarkers for myocardial injury, rising within 3–4 hours and remaining elevated for up to 14 days post-MI.
Question 4: A urine protein-to-creatinine ratio (UPCR) of 0.45 g/g in a patient with diabetes indicates which level of kidney involvement?
- Normal urine protein excretion
- Microalbuminuria only
- Significant proteinuria consistent with diabetic nephropathy (Correct answer)
- Nephrotic-range proteinuria
Correct answer: Significant proteinuria consistent with diabetic nephropathy
A UPCR above 0.3 g/g represents significant proteinuria; in a diabetic patient, 0.45 g/g is consistent with macroalbuminuria (overt diabetic nephropathy), indicating need for aggressive management.
Question 5: What does a right shift in the oxyhemoglobin dissociation curve indicate clinically?
- Hemoglobin has increased affinity for oxygen
- Hemoglobin releases oxygen more readily to tissues (Correct answer)
- Carbon monoxide poisoning is present
- Alkalosis is causing hemoglobin to hold oxygen tightly
Correct answer: Hemoglobin releases oxygen more readily to tissues
A right shift (caused by acidosis, hyperthermia, elevated CO2, or 2,3-DPG) decreases hemoglobin's oxygen affinity, facilitating oxygen unloading to metabolically active tissues.
Question 6: Which spirometry pattern is characteristic of obstructive lung disease such as COPD?
- Reduced FVC with normal FEV1/FVC ratio
- Reduced FEV1/FVC ratio (less than 0.70) with normal or mildly reduced FVC (Correct answer)
- Proportional reduction in both FEV1 and FVC
- Normal FEV1 with markedly elevated FVC
Correct answer: Reduced FEV1/FVC ratio (less than 0.70) with normal or mildly reduced FVC
Obstructive lung disease is defined by a post-bronchodilator FEV1/FVC ratio less than 0.70, reflecting airflow limitation due to airway narrowing with relatively preserved lung volumes.
AANPCB AANPCB Diagnostic Testing and Interpretation 2
Which finding on a complete blood count (CBC) is most consistent with iron deficiency anemia?