CRP and tuberculosis: At a tuberculosis prevalence of 10%, the W4SS would result in 604 rapid diagnostic tests being needed; C-reactive protein (≥10 mg/L) would reduce the number of rapid diagnostic tests needed by 293 but miss five additional tuberculosis cases, and chest x-ray (with any abnormality) would reduce the number of rapid diagnostic tests needed by 190, but miss ten additional tuberculosis cases (figure 3; appendix pp 29–31).