Combination of molecular assay and clinical evaluation for early confirmation of tuberculosis cases

Abstract The cost‐effectiveness of the ProbeTec ET Direct TB assay (DTB) was compared with that of culture for detection of Mycobacterium tuberculosis complex in 361 acid‐fast stain‐positive respiratory specimens. The overall sensitivity, specificity, positive predictive value and negative predictive value of DTB were 97.7%, 86.6%, 87.2% and 97.6%, respectively. When clinical evaluation was added to DTB, the specificity and positive predictive value of DTB increased to 94.7% and 95.4%, respectively. Treatment costs of $133 521 would have been saved in this cohort if DTB, instead of culture results, had been used to eliminate ‘false‐positive' smear results.