Specific tests that have evidence supporting their use in reducing mortality and are recommended to target treatment/prophylaxis to patients with HIV and low CD4 cell counts include tuberculosis (TB) smear, Xpert MTB/RIF and urinary lipoarabinomannan (LAM) for TB, and cryptococcal antigen (CrAg) to detect cryptococcal infection (Table 1). Here, CD4 is linked to tuberculosis.