Evaluation of three commercial detection systems for Mycobacterium tuberculosis where clinical diagnosis is difficult.

Abstract

The manufacturers of these systems recommend that they should only be used for the direct analysis of respiratory specimens, and the US Food and Drug Administration has approved them for use only with smear positive specimens. This study confirms that sensitivities are lower for non-respiratory and smear negative specimens, but positive predictive values are high. Provided they are interpreted with caution, positive results with these tests in respiratory and non-respiratory specimens are useful in tuberculous patients who are otherwise difficult to diagnose. Each amplification has advantages and disadvantages compared with the others.