COMPARISON OF THE MUREX CANDIDA-ALBICANS CA50 TEST WITH GERM TUBE PRODUCTION FOR IDENTIFICATION OF CANDIDA-ALBICANS

A total of 502 yeast isolates were tested with the 30-min MUREX Candid a albicans CA50 (Norcross, GA) test for presumptive identification of C. albicans. The results were compared with the standard 2-h germ tube test, which was the reference standard. Of the 502 isolates, 316 were C. albicans and 186 were non-C. albicans. Identifications were based on germ tube reactions; the API20C and chlamydospore agars were used w hen discrepant results persisted between the germ tube and MUREX test after repeat testing of the MUREX method. A total of 16 C. albicans ga ve negative results on initial testing with the MUREX test but were in terpreted as positive when repented. Three germ tube negative yeasts i nitially tested positive with the MUREX but were negative when repeate d. Two additional yeast isolates gave incorrect results with the MUREX , even with repeat testing: C. albicans and C. lusitaniae. The initial sensitivity and specificity for the MUREX C. albicans CA50 test were 94.6% and 97.8%, respectively. As an addition to the study, two fetal bovine sera were compared for production of germ tubes: fetal bovine s erum and Fetal Clone II. The testing found them to be in 100% agreemen t.