Recently, a study (Luo Y. et al., 2020) of the iron metabolism in serum between fairly large cohorts of active TB patients (n = 191) and LTBI (n = 154) found that the combination of iron metabolism indexes and TB-specific antigen/phytohemagglutinin (TBAg/PHA) ratio (>0.22) showed AUC = 0.93 with 89% sensitivity and 90% specificity in the training data set and AUC = 0.965 with 92% sensitivity and 91% specificity in the validation set, in distinguishing active TB from LTBI. The gene discussed is LBR; the disease is tuberculosis.