CD4 and tuberculosis: Due to these particularities, the relevance of sputum smear microscopy for the diagnosis of TB where GeneXpert is available is questioned, although evidence found shows that the concomitant use of both tests can result in an increase in the identification of cases not detected by both an exam and on the other28,30, mainly in people with T CD4+ lymphocyte count < 200 cells/μl30.