Comparative evaluation of the Iatron serological Candida check kit and the API 20C kit for identification of medically important Candida species.

A newly developed commercial serological test (Iatron Laboratories, Inc., Tokyo, Japan) for the rapid identification of medically important species of Candida was evaluated against the API 20C (Analytab Products, Plainview, N.Y.) and the standard Wickerham assimilation and fermentation procedures. Our results indicated that the Iatron and the API 20C methods are 95% accurate since both permitted identification of 78 of 82 Candida isolates, representing eight medically important species. None of the tests on nine Cryptococcus, six Trichosporon, three Geotrichum, three Saccharomyces, and one Rhodotorula species yielded false-positive reactions. False-positive serological tests occurred with a species of Pichia and Candida rugosa. The API 20C procedure correctly identified C. rugosa but not the Pichia sp. The Iatron method permitted reliable identification of the Candida species in 10 min to 5 h, whereas the API 20C procedure required 48 to 72 h. Neither method could properly identify sucrose-negative Candida tropicalis or Candida lusitaniae isolates. In addition, Candida albicans isolates could be serotyped by the Iatron method.