Evaluation of the hyplex TBC PCR test for detection of Mycobacterium tuberculosis complex in clinical samples.

backgroundTuberculosis (TB) is one of the major public health concerns worldwide. The detection of the pathogen Mycobacterium tuberculosis complex (MTBC) as early as possible has a great impact on the effective control of the spread of the disease. In our study, we evaluated the hyplex TBC PCR test (BAG Health Care GmbH), a novel assay using a nucleic acid amplification technique (NAAT) with reverse hybridisation and ELISA read out for the rapid detection of M. tuberculosis directly in clinical samples.

resultsA total of 581 respiratory and non-respiratory specimens from our pneumological hospital and the National TB Institute of Uzbekistan were used for the evaluation of the PCR assay. Of these, 292 were classified as TB samples and 289 as non-TB samples based on the results of the TB cultures as reference method. The PCR results were initially used to optimise the cut-off value of the hyplex TBC test system by means of a ROC analysis. The overall sensitivity of the assay was determined to be 83.1%. In smear-positive TB samples, the sensitivity of the hyplex TBC PCR test was estimated to 93.4% versus 45.1% in smear-negative samples. The specificity of the test was 99.25%. Of the two specimens (0.75%) with false-positive PCR results, one yielded a culture positive for non-tuberculous mycobacteria. Based on the assumption of a prevalence of 8% TB positives among the samples in our diagnostic TB laboratory, the positive and negative predictive values were estimated to 90.4% and 98.5%, respectively.

conclusionsThe hyplex TBC PCR test is an accurate NAAT assay for a rapid and reliable detection of M. tuberculosis in various respiratory and non-respiratory specimens. Compared to many other conventional NAAT assays, the hyplex TBC PCR test is in a low price segment which makes it an attractive option for developing and emerging countries with high TB burdens.