HP and tuberculosis: Bayes’ theorem was also used to calculate the PPV and NPV of using CD177 alone or the combination of CD177, HP, IGJ, and CLC to discriminate active TB from other infections, and the combination of BATF2, CD177, HP, IGJ, and CLC to discriminate active TB from either healthy states or other infections for a range of pretest probabilities, revealing the optimal PPV or NPV that can be achieved (Figure 12).