Organ System Pathology USMLE Step 1 Practice Question
A 58-year-old woman presents with nephrotic syndrome (proteinuria 8 g/day, serum albumin 2.1 g/dL) and normal complement levels. Vital signs: BP 148/92, HR 88, RR 16, Temp 37°C, SpO2 98%. She denies recent infections and takes no immunosuppressants. Kidney biopsy shows glomerular deposits. The pathologist suspects amyloidosis. Which stain would demonstrate apple-green birefringence under polarized light microscopy if amyloidosis is confirmed?
Answer choices
- AMucicarmine
- BCongo redCorrect answer
- CPrussian blue
- DPeriodic acid Schiff
- EMasson trichrome
- FThioflavin S
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