Diagnostic Value of the Amplicor PCR Assay for Initial Diagnosis and Assessment of Treatment Response for Pulmonary Tuberculosis

Abstract

We evaluated the Amplicor PCR assay as an initial diagnostic tool on the basis of clinical diagnosis, and assessed this assay as a follow-up test for patients with pulmonary tuberculosis during chemotherapy. Of the 208 specimens from 155 patients who were bacteriologically and/or clinically diagnosed with active tuberculosis before chemotherapy, 144 were Amplicor PCR-positive (sensitivity, 69.2%), which was equal to the results of culturing. Among 89 specimens which showed positive results by smear and culturing, the Amplicor PCR assay detected 87 (97.8%), whereas among 55 specimens which showed smearnegative but culture-positive results, the Amplicor PCR assay detected 46 (83.6 %)(P= 0.003). No false positive results were found in the two systems (specificity, 100%, 120/120). The Amplicor PCR assay was also evaluated as a follow-up test using 926 specimens from 207 patients receiving active tuberculosis chemotherapy. Among 433 specimens which showed Amplicor-PCR positive, 222 (51.3%) were culture-negative. On the other hand, among 233 culture-positive specimens, only 12 (5.2%) were Amplicor PCR-negative. Therefore, this assay is useful for the rapid diagnosis of tuberculosis. The duration of Amplicor PCR-positive after culture-negative conversion was significantly associated with the presence of cavitary lesion, smearpositive specimens before treatment, and smear-positive specimens with negative cultures during chemotherapy.

Evaluation of Commercial DNA and rRNA Amplification Assays for Assessment of Treatment Outcome in Pulmonary Tuberculosis Patients

“…1 and 2). As found in previous studies [6][7][8]10], the results of both amplification assays remained positive longer than those of culture and smear. The collection of multiple sputum specimens improved the sensitivity of the assays but did not provide any benefit in clinical follow-up.…”

“…Moreover, like us, they found no correlation with the radiographic extent of disease. In contrast to the observations of Iinuma et al [7] and Yuen et al [14], we found no association between positive PCR and AMTDT results and initial sputum smear positivity, presence of cavitary disease or radiographic extent of tuberculosis. This is likely due to the heterogeneity of the study populations.…”

“…The Amplified Mycobacterium Tuberculosis Direct Test (AMTDT 2; Gen Probe, USA) and the Cobas Amplicor Mycobacterium Tuberculosis Test (Roche, Switzerland) are highly standardized and automated second-generation assays for detection of Mycobacterium tuberculosis, with reported sensitivities of 86-100% and 83-98%, and specificities of 94-100% and 92-100%, respectively [1,[3][4][5]. Following studies in which controversial results were obtained with various amplification assays, the role of these assays in monitoring treatment response remains undefined [6][7][8][9]. Previously, the results of polymerase chain reaction (PCR) assays have remained positive longer than the results of culture during tuberculosis treatment [6,10], indicating detection of nonviable tuberculous bacteria [8,10].…”

Diagnosis of tuberculosis: Available technologies, limitations, and possibilities

“…Other phospholipids. Antituberculophospholipid antibodies as serological markers have been reported to have a sensitivity and specificity of 86.9% and 100%, respectively (59). Acyltrehaloses are among the strongest antigenic glycolipids of M. tuberculosis.…”

Evaluation of a Commercially Available Serologic Assay for Antibodies against Tuberculosis-associated Glycolipid Antigen

“…The NAA assay was performed according to the manufacturer's instructions (17). Briefly, samples were treated with Nacetyl-L-cysteine (NALC)-NaOH, lysed, and neutralized.…”