Test : India Ink Preparation
Indications : India Ink preparation is usually employed to detect the presence of
microorganisms, particularly yeast, in a body fluid. It induces negative staining by creating a black, semi-opaque background that makes the capsule of the yeast clearly visible.
One drop of cerebrospinal fluid (CSF) is mixed with a drop of India Ink on a clean micro slide.A cover slip is placed over it and the sample is examined through the low power lens, and then through the high power lens, of a microscope. The preparation can be diluted with a small drop of water if it is too dark and murky.
Physiology : 'India Ink' is a type of ink that was once commonly used for writing, drawing and in printing. It has a few medical applications too, such as screening for C. neoformans, and
yeast and a few forms of
fungi.
India Ink Preparation is a test to detect the presence of Cryptococcus neoformans, a type of encapsulated yeast that is capable of surviving in both animals and plants. It is usually found in soil that is extremely contaminated with bird droppings.
C. neoformans is the most common of the
central nervous system pathogens. It can cause harmless colonization of human airways but can also lead to
meningitis or disseminated disease in immune-compromised persons, such as those with
AIDS. It also affects skin, lungs, spleen, kidneys, liver and bones.
Normal Range : No cryptococcus identified
Interpretation : No
Cryptococcus neoformans is identified in a normal sample while its presence can be detected in an abnormal sample. The infection can be treated with oral
anti-fungal medications.
Sample : Fungal specimen
Test Method : Wt mount with india ink for contrast
Related Tests : Cerbrospinal fluid culture, Cryptococcus antigen titer, KOH preparation
Careers
How is india ink preparation carried out and what are the components