We also determined the prevalence of IDA according to a range of seven different published definitions for IDA.4,12–16 Finally, as high hepcidin concentrations have strong predictive value for non-responsiveness to oral iron therapy,17 we determined the proportion of HIV-associated TB patients who had both IDA and low hepcidin concentrations, as this defines a patient subgroup that may benefit from oral iron supplementation during their treatment course. The gene discussed is HAMP; the disease is tuberculosis.