EVALUATION OF NEW RAPID COMMERCIAL ENZYME-IMMUNOASSAY FOR DETECTION OF CRYPTOSPORIDIUM OOCYSTS IN UNTREATED STOOL SPECIMENS

Sixty-six stool specimens were evaluated by the ProSpecTR Cryptosporid ium rapid enzyme immunoassay (EIA) (Alexon, Sunnyvale, Calif.). Approx imately 2 g of untreated stool suspended in buffer was filtered throug h membranes labelled with anti-Cryptosporidium-specific antigen antibo dy. Anti-Cryptosporidium-specific antigen antibody was labelled with b iotin, horseradish peroxidase conjugated to streptavidin, and tetramet hylbenzidine, and each labelled antibody was added in sequence to the membranes. Each membrane had a positive control and test area. EIA res ults were compared with those of the modified acid-fast procedure. Twe nty-three specimens were positive by the initial acid-fast procedure a nd the EIA. Forty-two specimens were negative by the initial acid-fast test and the EIA. One specimen was negative by the initial acid-fast test and positive by the EIA (sensitivity, 100%; specificity, 98.5%). This technique is easy to use by comparison with the cumbersome, labor -intensive, and more subjective microscopic methods currently availabl e, and its sensitivity equals that of current microscopic methods.