Lab method
India ink preparation
Negative stain that reveals a capsule halo
High-yield clue
A clear halo around budding yeast in cerebrospinal fluid is the classic India ink clue for the Cryptococcus capsule.
Overview
A negative (background) staining concept where opaque ink particles cannot enter an organism's capsule, so an unstained clear halo appears around the cell against a dark field.
Classification
- Negative stain concept
- Wet-mount light microscopy
- Capsule visualization
- Non-specific method
Lab & identification clues
- Clear unstained halo against dark background
- Narrow-based budding yeast inside the halo vocabulary
- Capsule excludes ink particles
- Lower sensitivity than antigen testing vocabulary
Associations
- Cryptococcus in CSF study association
- Encapsulated yeast recognition
- Meningitis workup vocabulary
Commonly confused with
- Gram stain
- Calcofluor white stain
Your notes
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.