Evaluation of polimerase chain reaction-enzyme linked immunoassay (PCR-ELISA) for direct detection of mycobacterium tuberculosis in clinical specimens

In controlling of Tuberculosis (TB), early diagnosis of disease caused by Mycobacterium tuberculosis complex (MTBC) is vital. Hence, nucleic acid amplification methods for rapid diagnosis of TB methods came to be used widely in recent years. PCR-ELISA is among nucleic acid amplification based methods that are used for the direct detection of MTBC in clinical samples.In this study, PCR-ELISA (ProDect MYCOBACTERIUM TUBERCULOSIS- ProDect GEN E.I.A., bcs Biotect S.p.A., Cagliari, Italia) was evaluated for detection of MTBC in pulmonary and extrapulmonary clinical samples. 100 clinical samples (76 pulmonary and 24 extrapulmonary) from patients suspected of TB were assested by microscopy, culture and PCR-ELISA methods. When PCR-ELISA test results were compared to culture results taken as the gold standard, the sensitivity, specificity, positive and negative predictive values (PPV and NPV) for whole specimens were found to be 68.2%, 94.1%, 95.7% and 60.4%, respectively. The sensitivity, specificity, PPV and NPV were 77.1%, 93.5%, 94.1%, 69.0% for pulmonary specimens and 61.9%, 100%, 100%, 27.3% for extrapulmonary specimens, respectively. For smear positive pulmonary specimens, the sensitivity and specivity were found to be 83.3% and 100%, respectively.In conclusion, PCR-ELISA method can be utilized cost-effectively, providing results with the use of less equipment, as a routine nucleic amplification test for the rapid diagnosis of tuberculosis in a mycobacteriology laboratory, specifically for smear positive pulmonary samples.