Cat. no. Z64 India Ink, 0.5oz. Polyethylene Dropper Bottle, 15ml 1 bottle


Hardy Diagnostics India Ink is recommended for use in the identification of Cryptococcus neoformans.


Cryptococcus neoformans, because of its large polysaccharide capsule, can be visualized by the India Ink stain. Organisms that possess a polysaccharide capsule exhibit a halo around the cell against the black background created by the India Ink.



Storage: Upon receipt store at 2-30ºC away from direct light. Product should not be used if there are any signs of deterioration, contamination, or if the expiration date has passed. Product is light and temperature sensitive; protect from light, excessive heat, moisture, and freezing.



Specimen Collection: Specimens should be collected in sterile containers or with sterile swabs and transported immediately to the laboratory. This product is used in conjunction with other biochemical and serological tests to identify cultures of isolated organisms.

Method of Use: Mix the specimen with a small drop of India Ink on a clean glass slide. Place a cover slip over the smear and press gently. The preparation should be brownish, not black. Using reduced examine the smear microscopically (100X) for the presence of encapsulated cells as indicated by clear zones surrounding the cells.

Note: The India Ink is ready to use. Further dilution with water is not recommended.

Note: Production of capsular material may be increased by cultivation in a 1% peptone solution (Peptone Broth, Cat. no. K151).(7)


The India Ink test may be used in the presumptive identification of C. neoformans. Culture, biochemical and serological testing is recommended for complete identification.

The diagnosis of C. neoformans by negative staining should be considered a presumptive result. Leukocytes, fat droplets, and tissue cells are sometimes confused with C. neoformans cells. Leukocytes and tissue cells may be dissolved by adding a drop of 10% KOH.

Some strains of C. neoformans, as well as other cryptococci may not produce discernible capsules in vitro.(7)


Standard microbiological supplies and equipment such as loops, glass slides, coverglass, microscopes, incinerators, and incubators, etc., as well as serological and biochemical reagents, are not provided.


Test Organisms Results
Cryptococcus neoformans
ATCC® 32045
Candida albicans
ATCC® 10231


Physical Appearance

India Ink should appear opaque, and black in color.


1. Versalovic, J., et al. Manual of Clinical Microbiology. American Society for Microbiology, Washington, D.C.

2. Tille, P., et al. Bailey and Scott's Diagnostic Microbiology, C.V. Mosby Company, St. Louis, MO.

3. Anderson, N.L., et al. Cumitech 3B; Quality Systems in the Clinical Microbiology Laboratory, Coordinating ed., A.S. Weissfeld. American Society for Microbiology, Washington, D.C.

4. Haley, L.D. and C.S. Callaway. 1978. Laboratory Methods in Medical Mycology, U.S. Department of Health, Education and Welfare, Atlanta, Georgia.

5. Isenberg, H.D. Clinical Microbiology Procedures Handbook, Vol. I, II & III. American Society for Microbiology, Washington, D.C.

6. Koneman, E.W., et al. Color Atlas and Textbook of Diagnostic Microbiology, J.B. Lippincott Company, Philadelphia, PA.

7. Larone, D.H. Medically Important Fungi: A Guide to Identification, American Society for Microbiology. Washington, D.C.

8. Commission on Laboratory Accreditation, Laboratory Accreditation Program Microbiology Checklist. College of American Pathologists. Rev. 9/30/2004.

9. Centers for Medicare and Medicaid, Appendix C, Survey Procedures and Interpretive Guidelines for Laboratories and Laboratory Services. Subpart K - Quality System for Non-Waived Testing. 493;1200-1265.

ATCC is a registered trademark of the American Type Culture Collection.