Pathology · single question
Which test is used to confirm a diagnosis of pemphigus vulgaris?
Show answer and explanation
Correct answer: A. Direct/indirect immunofluorescence
- A. Correct. Direct immunofluorescence shows the intercellular 'fishnet' IgG deposition between keratinocytes that is diagnostic of pemphigus.
- B. Incorrect. Gram stain identifies bacteria, not autoimmune blistering disease.
- C. Incorrect. PAS highlights fungal organisms (e.g., Candida), not pemphigus autoantibodies.
- D. Incorrect. Pemphigus is autoimmune, not infectious; culture is unhelpful.