A recent study conducted in Cape Town found that, of 139 HIV-positive individuals diagnosed with TB during admission to hospital (median CD4 count 80 cells/μL; 35% on ART for a median 1.3 years), 115 (83%) had at least one non-respiratory sample that was positive on testing with Xpert® MTB/RIF, or culture positive for M. tuberculosis [34]. This evidence concerns the gene CD4 and tuberculosis.