What is the role of cryptosporidium tests in the workup of cryptosporidiosis?

Updated: Nov 11, 2019
  • Author: Melinda B Tanabe, MD; Chief Editor: Michael Stuart Bronze, MD  more...
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Answer

Many laboratories do not routinely test for Cryptosporidium, and, in many instances, the tests used to evaluate for this organism are insensitive. [1] Studies in the United States have documented cryptosporidiosis in about 4% of stools sent for parasitologic examination, while, overall, about 13% of stool studies submitted for parasitologic studies in developing countries reveal Cryptosporidium oocysts.

Cryptosporidium infection can be difficult to diagnose via standard methods and is often missed unless specific tests are performed. Traditionally, it was diagnosed via microscopic examination with special staining techniques (eg, acid-fast staining, direct fluorescent antibody [DFA], enzyme immunoassays, or immunochromatographic tests for detection of Cryptosporidium antigens) (See the image below.) [44] Currently, PCR multiplex molecular tests have widely increased sensitivity and specificity.

Modified acid-fast stain of stool shows red oocyst Modified acid-fast stain of stool shows red oocysts of Cryptosporidium parvum against the blue background of coliforms and debris.

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