Accuracy of the chest x-ray in screening for tuberculosis in Uganda: A cross-sectional study.

Abstract

BACKGROUND: The WHO END TB strategy requires ≥90% case detection to combat tuberculosis (TB). Increased TB case detection requires a more sensitive and specific screening tool. Currently, the symptoms recommended for screening TB have been found to be sub-optimal. CXR as a screening tool for pulmonary TB was evaluated in this study, as well as factors related to its false positive results. METHODS: A cross sectional study of 4441 records of consented/assented participants ≥15 years. Participants with a cough ≥2 weeks and/or any abnormality in the lung on CXR were included in the study. Löwenstein-Jensen (LJ) culture was used as the gold standard. The CXR were categorised as Abnormal meaning presence of any CXR abnormality suggestive of active tuberculosis. Symptoms were categorised as abnormal meaning presence of any of cough ≥ 2 weeks, fever, weightloss or night sweats. RESULTS: The CXR had sensitivity 93%, specificity 65% compared to culture results while symptoms had sensitivity 76% and specificity 31%. The adjusted prevalence ratio (APR) of a false positive CXR result increased with age categories (years); 45 - 54, APR 1.18 (1.08, 1.29), 55 – 64 APR 1.18 (1.09, 1.29), 65+years APR 1.2 (1.10, 1.30).The APR was 0.93 (0.90, 0.96) among males and 0.86 (0.79, 0.93) among HIV positive individuals. CONCLUSIONS: The CXR is a fair tuberculosis screening tool and performed better than symptoms in Uganda.