Lab method
GMS silver stain
Silver stain making fungi and Pneumocystis black
G-M-S
High-yield clue
GMS turning organisms black is the classic tissue clue for fungi and for Pneumocystis jirovecii cysts.
Overview
Grocott-Gomori methenamine silver is a histopathology stain in which silver deposits onto fungal cell walls (and Pneumocystis), rendering them black against a pale green counterstain.
Classification
- Silver impregnation concept
- Tissue/histology stain
- Fungal cell-wall stain
- Light microscopy
Lab & identification clues
- Black organisms on pale green background
- Highlights hyphae, yeast, and cyst walls
- Pneumocystis crushed 'ping-pong ball' cyst vocabulary
- Used on biopsy sections
Associations
- Pneumocystis pneumonia tissue association
- Invasive mold detection vocabulary
- Fungal histopathology recognition
Commonly confused with
- Calcofluor white stain
- Acid-fast stain
Frequently asked questions
What is GMS silver stain?
Grocott-Gomori methenamine silver is a histopathology stain in which silver deposits onto fungal cell walls (and Pneumocystis), rendering them black against a pale green counterstain.
What is the high-yield clue for GMS silver stain?
GMS turning organisms black is the classic tissue clue for fungi and for Pneumocystis jirovecii cysts.
What is GMS silver stain associated with?
GMS silver stain is associated with Pneumocystis pneumonia tissue association, Invasive mold detection vocabulary, and Fungal histopathology recognition.
What is GMS silver stain commonly confused with?
GMS silver stain is commonly confused with Calcofluor white stain and Acid-fast stain.
Original concept summary for coursework. Sources checked: OpenStax Microbiology 2e and NCBI Bookshelf Medical Microbiology; reviewed 2026-06. Describes vocabulary and interpretation concepts only; not a lab protocol and not for handling specimens or identifying patient isolates.