Impact of larger sputum volume on xpert® MTB/RIF assay detection of mycobacterium tuberculosis in smear-negative individuals with suspected tuberculosis

Abstract

As a strategy to improve the sensitivity of nucleic acid-based testing in acid-fast bacilli (AFB) negative samples, larger volumes of sputum (5–10 mL) were tested with Xpert® MTB/RIF from 176 individuals with smear-negative sputum undergoing tuberculosis evaluation. Despite larger volumes, this strategy had a suboptimal sensitivity of 50% (4/8).