DIAGNOSIS OF EXTRAPULMONARY TUBERCULOSIS BY GEN-PROBE AMPLIFIED MYCOBACTERIUM-TUBERCULOSIS DIRECT TEST

A total of 294 specimens collected from nonrespiratory sites of 268 pa tients were tested for direct detection of Mycobacterium tuberculosis complex by the Gen-Probe Amplified Mycobacterium tuberculosis Direct T est (AMTD). The specimens included ascitic, pleural, pericardial, add synovial fluids, abscess aspirates, and tissue and lymph node biopsy s amples, as well as gastric aspirates and cerebrospinal fluid samples. All samples were processed by the N-acetyl-L-cysteine-sodium hydroxide decontamination procedure prior to testing. Twenty samples showed aci d-fast bacilli on auramine staining, and 48 samples were positive by A MTD, 9 of which were negative for M. tuberculosis complex by culture. After reviewing the patients' clinical charts to resolve discrepancies , the test result of one cerebrospinal fluid sample was considered to be false positive by AMTD. The overall sensitivity, specificity, posit ive predictive value, and negative predictive value were 83.9, 99.6, 9 7.9, and 96.3%, respectively. No significant differences were found wh en AMTD results obtained with specimens of nonrespiratory origin were compared with assay results obtained with samples of respiratory origi n (P > 0.05). In conclusion, our results demonstrate that AMTD perform s equally well with all types of specimens.