Evaluation of the COBAS AMPLICOR MTB test for the detection of Mycobacterium tuberculosis complex

Abstract

We evaluated the COBAS AMPLICOR polymerase chain reaction [‎PCR]‎ based test for the detection of Mycobacterium tuberculosis complex in 866 respiratory and non-respiratory samples. Acid-fast staining and culture on Lowenstein-Jensen medium were also performed on all samples. Of the 866 samples tested, 87 [‎10.0%]‎ were PCR-positive compared to 94 [‎10.9%]‎ culture positive. There were no false positive results but 7 PCR-negative, culture-positive samples were, considered false negatives after reviewing medical records of patients. A PCR inhibitory rate of 2.0% [‎17/866]‎ was observed in respiratory samples only. Sensitivity, specificity, and positive and negative predictive values for this test were 92.5%, 100%, 100% and 99.1% respectively. This test is a valuable diagnostic tool for today's mycobacteriology laboratory