Urine colorimetry for therapeutic drug monitoring of pyrazinamide during tuberculosis treatment.

Objectives: Pyrazinamide is a key drug in the first-line treatment regimen for tuberculosis, with a potent sterilizing effect. Although low pyrazinamide peak serum concentrations (C) are associated with poor treatment outcomes, many resource-constrained settings do not have sufficient laboratory capacity to support therapeutic drug monitoring (TDM). The objective of this study was to determine whether a colorimetric test of urine can identify tuberculosis patients with adequate pyrazinamide exposures, as defined by serum C above a target threshold.