Diagnostic accuracy and clinical role of rapid C-reactive protein testing in HIV-infected individuals with presumed tuberculosis in South Africa

OBJECTIVE: To determine the accuracy and role of rapid C-reactive protein (CRP) testing in human immunodeficiency virus (HIV) infected individuals with presumed tuberculosis (TB). DESIGN: We enrolled REV-infected adults (>= 18 years) with a cough of >= 2 weeks and negative sputum smears for acid-fast bacilli in KwaZulu-Natal, South Africa. Participants were evaluated for pulmonary TB (PTB) by a nurse with rapid CRP, and independently by a physician by chest radiograph. Rapid CRP test results were compared with laboratory CRP and sputum sent for confirmation of TB. RESULTS: Among 93 participants, 55 (59%) were female, the mean age was 35 years, and the median CD4 count was 177/mm(3). Forty-five (54%) participants were diagnosed with PTB. Diagnostic sensitivity and specificity were respectively 95% (95%CI 74-99) and 51% (95%CI 35-66) for rapid CRP >8 mg/l,87% (95%CI 73-96) and 53% (95 %CI 38-68) for nurse assessment, and 69% (95%CI 52-83) and 76% (95%CI 61-87) for physician examination. Combining a negative rapid CRP <= 8 mg/l) with nurse and physician assessments reduced the post-test probability of PTB from 22% to 6% and from 32% to 6%, respectively. CONCLUSION: Rapid CRP testing helped exclude PTB, and may be a valuable test in assisting nurses and physicians in TB-endemic regions.