OBJECTIVE: To evaluate validity of WHO staging, low body mass index (BMI) and anaemia in detecting HIV-infected adults with CD4+ T-cell counts < 200 cells/microl. METHODS: Between October 1995 and April 2006, we screened Ugandans aged 16 or older at enrollment into an open cohort. We analysed highly active anti-retroviral therapy (HAART)-naïve HIV-infected patients with WHO stages 1-3 and complete data in a secondary cross-sectional study. Low BMI was a BMI < 18.5 kg/m(2). Anaemia was a haemoglobin level < 11 or 12 g/dl among women and men respectively. RESULTS: Among 2892 HAART-naïve patients, the median age was 32 years. 71% were women, 54% had WHO stage 3 AIDS, 34% had anaemia, 16% had a low BMI and 43% had CD4+ T-cell counts < 200 cells/microl. WHO stage 3 compared to combined WHO stages 1 and 2 had a sensitivity (95% CI) of 70% (67, 72) and a specificity of 57% (55, 60) respectively to detect CD4+ T-cell counts < 200 cells/microl. Anaemia compared to normal haemoglobin had sensitivity (95% CI) of 47% (44, 50) and a specificity of 76% (74, 78). Low BMI compared to normal BMI had sensitivity (95% CI) of 23% (20, 25) and a specificity of 89% (87, 90) against CD4+ T-cell counts < 200 cells/microl. CONCLUSION: Only WHO stage 3 had reasonably high sensitivity in detecting CD4+ T-cell counts below 200 cells/microl in this setting. Targeted low-cost CD4 testing strategies are urgently needed to detect patients eligible for HAART in rural Africa and other resource-limited settings.