25-09: Cerebrospinal Fluid Examination—India Ink Preparation for Cryptococcus Neoformans

Uses

To examine cerebrospinal fluid for organisms with capsules, particularly Cryptococcus neoformans.

Materials

India Ink, glass microscope slide, and coverslip.

Method

1. Lightly centrifuge cerebrospinal fluid to concentrate cells at bottom of tube (1-2 minutes).

2. Pour off excess fluid (retain if further testing may be necessary).

3. Take a drop from the bottom of the centrifuge tube and place it in the middle of a glass microscope slide.

4. Place a drop of India Ink into the specimen drop; gently mix.

5. Overlay a coverslip.

6. Examine at ×10 to screen specimen; use ×40 objective to confirm findings.