Mayo Test Catalog, (Sorted By Test Name) - Mayo Medical ...

CRYPS
80335
SFC
8719
Clinical Information: Cryptococcosis is an invasive fungal infection caused by Cryptococcus
neoformans. The organism has been isolated from several sites in nature, particularly weathered pigeon
droppings. Infection is usually acquired via the pulmonary route. Patients are often unaware of any
exposure history. Approximately half of the patients with symptomatic disease have a predisposing
immunosuppressive condition such as AIDS, steroid therapy, lymphoma, or sarcoidosis. Symptoms may
include fever, headache, dizziness, ataxia, somnolence, and cough. In addition to the lungs, cryptococcal
infections frequently involve the central nervous system (CNS), particularly in patients infected with HIV.
Mortality in CNS cryptococcosis may approach 25% despite antibiotic therapy. Untreated CNS
cryptococcosis is invariably fatal. Disseminated disease may affect any organ system and usually occurs
in immunosuppressed individuals.
Useful For: Aiding in the diagnosis of cryptococcosis
Interpretation: The presence of cryptococcal antigen in any body fluid is indicative of cryptococcosis.
Higher titers appear to correlate with more severe infections. Declining titers in urine or serum may
indicate regression of infection or response to therapy. However, monitoring titers to cryptococcal antigen
should not be used as a test of cure, as low level titers may persist for extended periods of time following
appropriate therapy and the resolution of infection. In addition to testing for cryptococcal antigen, patients
with presumed disease due to Cryptococcus neoformans should have clinical specimens (eg,
bronchoalveolar lavage fluid) submitted for routine smear and fungal culture.
Reference Values:
Negative
Clinical References: Hazen KC, Howell SA: Candida, Cryptococcus, and other Yeasts of Medical
Importance. In Manual of Clinical Microbiology. 9th edition. Edited by PR Murray. Washington, DC,
ASM Press, 2007, pp 1762-1788
Cryptosporidium Antigen, Feces
Clinical Information: Cryptosporidia are protozoa of the coccidian group which are common
parasites of livestock animals and can contaminate and survive in surface water supplies. Infection of
humans occurs by the fecal-oral route or by ingestion of contaminated water. The exact mechanism by
which the organism causes gastroenteritis is unknown. Cryptosporidiosis occurs as a profuse diarrhea in
patients with AIDS and as a self-limited moderate diarrhea in young children, especially daycare
attendees and their relatives.
Useful For: Establishing the diagnosis of intestinal cryptosporidiosis
Interpretation: A positive enzyme-linked immunosorbent assay (ELISA) indicates the presence of
antigens of cryptosporidium and is interpreted as evidence of infection with that organism. The
sensitivity, specificity, and positive predictive value of the ELISA were 87%, 99%, and 98% respectively,
as determined by examination of 231 fecal specimens by conventional microscopy and by ELISA.
Reference Values:
Negative
Clinical References: Soave R, Johnson WD Jr: Cryptosporidium and Isospora belli. J Infect Dis
1988;157:225-229
Crystal Identification, Synovial Fluid
Clinical Information: Birefringent crystals are found in the synovial fluid of >90% of patients with
acutely inflamed joints. Monosodium urate crystals are seen in gouty fluids and calcium pyrophosphate
crystals are seen in chondrocalcinosis. The urates are usually needle-shaped, and the calcium crystals are
often rhomboidal. Cholesterol crystals may also be observed.
Useful For: Providing a definitive diagnosis for joint disease
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