Cryptococcus is an encapsulated yeast-like fungus found in the soil worldwide. The major species of Cryptococcus that causes illness in human is Cryptococcus neoformans. It causes pulmonary and cerebromeningal infections in immunodeficient patients, especially those with AIDS. Cryptococcal infection may cause a pneumonia-like illness, with shortness of breath, coughing and fever. Skin lesions may also occur, and central nervous system infections such as cryptococcal meningocephalitis. This test detects the level of circulating antigens as they are useful for following disease progress, therapeutic monitoring, and the likelihood of recurrence.