In a modified trichrome stain of a fecal smear, microsporidia appear as which of the following?

• A. Pink ovals, 1-3 um in diameter
• B. Purple circles, 10-15 um in diameter
• C. Blue ovals, 4-6 um in diameter
• D. Fluorescent circles, 8-12 um in diameter

Answer: (A)

Microsporidia are tiny spores that the Weber modified trichrome stain highlights as bright pink. The key identifying feature is their very small size, about 1–3 micrometers, with an oval shape. That combination—pink, oval spores that are only around 1–3 μm in diameter—is what you’d expect to see on a fecal smear stained with this method. The other descriptions describe structures that are larger or colored differently, so they don’t match how microsporidia appear in this stain.