Rapid microbiological screening for tuberculosis in HIV-positive patients on the first day of acute hospital admission by systematic testing of urine samples using Xpert MTB/RIF: a prospective cohort in South Africa.

Background: Autopsy studies of HIV/AIDS-related hospital deaths in sub-Saharan Africa reveal frequent failure of pre-mortem diagnosis of tuberculosis (TB), which is found in 34-64 % of adult cadavers. We determined the overall prevalence and predictors of TB among consecutive unselected HIV-positive adults requiring acute hospital admission and the comparative diagnostic yield obtained by screening urine and sputum samples obtained on day 1 of admission with Xpert MTB/RIF (Xpert).

Methods: To determine overall TB prevalence accurately, comprehensive clinical sampling (sputum, urine, blood plus other relevant samples) was done and TB was defined by detection of Mycobacterium tuberculosis in any sample using Xpert and/or mycobacterial liquid culture.

Diagnostic yield of tuberculosis using sputum induction in HIV-positive patients before antiretroviral therapy.

Adults (n = 602) enrolling in a South African antiretroviral treatment clinic underwent culture-based screening for tuberculosis (TB), regardless of symptoms. For those unable to spontaneously expectorate a 'spot' sample (n = 124), sputum induction with nebulised hypertonic saline was used to obtain a first sample and also to rapidly obtain a second sample from all patients. Collection of both samples typically took 10-15 min.