Commercial cryptococcal latex kit: clinical evaluation in a medical center hospital

A commercial latex kit for the detection of cryptococcal antigen (LCAT) was used in a medical center hospital to test cerebrospinal fluid (CSF) and serum specimens from patients suspected of having cryptococcal infections. The LCAT was also performed on 8 CSF and 2 serum specimens from other mycotic infections and on 50 serum specimens from healthy controls. Of a total of 561 specimens (489 CSF and 72 sera) from 426 patients, 78 (13.9%) specimens were LCAT positive; these came from 12 patients with culturally proven cryptococcosis. Eleven of these 12 patients were diagnosed as having disseminated cryptococcosis (9 with meningitis). Fourteen other patients, all with positive cultures for Cryptococcus neoformans but nevative LCATs on sera or CSF, were found not to have disseminated infections. All CSF and sera from other mycotic infections and all 50 control sera were negative. No false positive or flase negative tests were encountered. It was concluded that the commercial kit is useful for diagnosis and prognosis of disseminated cryptococcosis, but not as useful for infections such as localized pulmonary or cutaneous cryptococcosis.