EVALUATION OF THE ROCHE AMPLICOR(TM) MTB ASSAY FOR THE DETECTION OF MYCOBACTERIUM-TUBERCULOSIS IN SPUTUM SPECIMENS FROM PRISON-INMATES

The reliability of the Roche Mycobacterium tuberculosis polymerase cha in reaction (PCR) assay (AMPLICOR(TM) MTB) for the diagnosis of pulmon ary tuberculosis was evaluated by testing expectorated sputum specimen s from 187 inmates in Texas state prisons and comparing the results to culture and medical history. Of the 80 specimens that were culture po sitive for mycobacteria, 36 specimens from 16 patients grew M. tubercu losis. Forty-six specimens were smear positive for acid-fast bacilli ( AFB), and of these, M. tuberculosis was isolated from 24. On initial t esting, 52 specimens were PCR positive. Thirty-one of these 52 were cu lture positive for M. tuberculosis, and 21 were culture negative, resu lting in a PCR sensitivity and specificity of 86.1 and 96.1%, respecti vely. After resolving discrepancies by review of the medical history a nd repeat testing, PCR sensitivity, specificity, and positive and nega tive predictive values, respectively, were 92.8, 99.8, 98.1, and 99.2% . For AFB smear-positive specimens, the sensitivity, specificity, and positive and negative predictive values, were 95.8, 100, 100, and 93.3 , respectively; whereas, for AFB smear-negative specimens, these value s were 87.5, 99.7, 95.5, and 99.4%, respectively These results confirm the reliability of the AMPLICOR(TM) MTB assay for direct detection of M. tuberculosis in AFB smear-positive sputum specimens and suggest a potential role in evaluating AFB smear-negative sputum specimens. (C) 1997 Elsevier Science Inc.