Cryptococcal antigen screening and preemptive therapy in patients initiating antiretroviral therapy in resource-limited settings: a proposed algorithm for clinical implementation.

HIV-associated cryptococcal meningitis (CM) is estimated to cause over half a million deaths annually in Africa. Many of these deaths are preventable. Screening patients for subclinical cryptococcal infection at the time of entry into antiretroviral therapy programs using cryptococcal antigen (CRAG) immunoassays is highly effective in identifying patients at risk of developing CM, allowing these patients to then be targeted with "preemptive" therapy to prevent the development of severe disease. Such CRAG screening programs are currently being implemented in a number of countries; however, a strong evidence base and clear guidance on how to manage patients with subclinical cryptococcal infection identified by screening are lacking. We review the available evidence and propose a treatment algorithm for the management of patients with asymptomatic cryptococcal antigenemia.