Asymptomatic cryptococcal antigen prevalence detected by lateral flow assay in hospitalised HIV-infected patients in São Paulo, Brazil

Objective: To determine the prevalence of asymptomatic cryptococcal antigen (CRAG) using lateral flow assay (LFA) in hospitalised HIV-infected patients with CD4 counts <200 cells/μl. Methods: Hospitalised HIV-infected patients were prospectively recruited at Instituto de Infectologia Emilio Ribas, a tertiary referral hospital to HIV-infected patients serving the São Paulo State, Brazil. All patients were >18 years old without prior cryptococcal meningitis, without clinical suspicion of cryptococcal meningitis, regardless of antiretroviral (ART) status, and with CD4 counts <200 cells/μl. Serum CRAG was tested by LFA in all patients, and whole blood CRAG was tested by LFA in positive cases. Results: We enrolled 163 participants of whom 61% were men. The duration of HIV diagnosis was a median of 8 (range, 1–29) years. 26% were antiretroviral (ART)-naïve, and 74% were ART-experienced. The median CD4 cell count was 25 (range, 1–192) cells/μl. Five patients (3.1%; 95%CI, 1.0–7.0%) were asymptomatic CRAG-positive. Positive results cases were cross-verified by performing LFA in whole blood. Conclusions: 3.1% of HIV-infected inpatients with CD4 <200 cells/μl without symptomatic meningitis had cryptococcal antigenemia in São Paulo, suggesting that routine CRAG screening may be beneficial in similar settings in South America. Our study reveals another targeted population for CRAG screening: hospitalised HIV-infected patients with CD4 <200 cells/μl, regardless of ART status. Whole blood CRAG LFA screening seems to be a simple strategy to prevention of symptomatic meningitis.