Rapid Molecular Detection of Tuberculosis

To the Editor: Boehme et al. (Sept. 9 issue) 1 report encouraging results on the use of an automated molecular test for Mycobacterium tuberculosis and resistance to rifampin (Xpert MTB/RIF). However, the population of patients with clinical tuberculosis who have negative cultures still poses a problem of interpretation, which was not discussed in the article. Among study patients whose samples were culture-negative but who had symptoms of tuberculosis, 29.3% had positive results on the automated test; these patients made up 4.3% of the total number of automated test–positive patients. In such patients, tuberculosis that was detected by the automated test may . . .