Cryptosporidiosis in HIV-infected patients: Diagnostic sensitivity of stool examination, based on number of specimens submitted

Objectives: To determine the optimal number of stool specimens needed for the diagnosis of cryptosporidiosis, Methods: Four hundred thirty-five admissions were reviewed (291 patients) in which stool specimens were examined for Cryptosporidium parvum oocysts (mean of 1.47 specimens per admission), using a modified acid-fast stain, The diagnostic yield of each specimen was determined, Results: Cryptosporidium parvum oocysts were found in 81 of 435 admissions (18.6%), Ninety-six percent of the positive cases were detected on the first stool specimen analysis, and 100% were detected by the second specimen, Conclusions: Examination of one specimen is generally appropriate for the diagnosis of cryptosporidiosis in a hospitalized patient with AIDS presenting with diarrhea, Examination of a second specimen may be appropriate if the first specimen is negative and there is a high clinical index of suspicion.