Coaglutination test (COA) for Cryptococcus neoformans circulating antigen detection in cerebral spinal fluid (CSF)

Abstract

We tested 82 CSF of 24 renal transplanted patients (RT) with cerebral cryptococcosis, 8 CSF of asymptomatic RT patients, 43 CSF of proven cryptococcosis cases (positive control) and 35 CSF of patients with other diseases (histoplasmosis, paracoccidioidomycosis and bacterial infections) as negative control. The RT CSF were cultured in Sabouraud agar slant added with sunflower seeds and both control and RT CSF were qualitatively examined by cryptococcosis latex test (Crypto-LA test). The COA test was developed both qualitatively and quantitatively. The highest titre encountered was 1:2048. No false reactions appeared among the controls. The diagnostic value demonstrated by Galen and Gambino's method was: sensitivity - 92.1%; specificity - 92.6% and efficiency - 92.3%. Besides that, the COA proved to be quick, exact and cheap, but it depends on CSF and sera pre-treatment, in order to avoid autoagglutination and increase its sensibility.