Figure 4
Predictive values of the Loopamp MTBC assay depending on sputum smear status and pre-test probability.
PPV: positive predictive value. NPV: negative predictive value. PoTP: post-test predictive value. The figure was drawn based on the sensitivity of 0.966 and specificity of 0.713 for smear-positive sputum samples and the sensitivity of 0.543 and specificity of 0.986 for smear-negative sputum samples. Pre-test probability has similar meaning to prevalence. Readers can simply input the prevalence in the country or area into pre-test probability. For example, in the area of prevalence of 5%, the pre-test probability may be 5% for screening setting. However, if clinical information is available, patient specific pre-test probability is preferred. For example, the pre-test probability may be 50% for a patients with chronic fever, history of TB contact, and a cavitation on X-ray even in an area with prevalence of 5%.
