Diagnosis Test of Real-time Polymerase Chain Reaction (RT-PCR) for Pulmonary Tuberculosis

Abstract

BACKGROUND: Pulmonary tuberculosis remains the leading cause of morbidity and mortality in Thailand. The microbiological detection of TB is important because of early and correct diagnosis, drug resistance testing and it ensures that the effective treatment can be achieved and in a timely manner. Mycobacterial culture is the gold standard diagnostic test. Currently, a real-time polymerase chain reaction (RT-PCR) assay, such as Allplex™ MTB/MDRe Detection, Seegene is commonly used.

OBJECTIVE: To evaluate the diagnosis value of the real-time multiplex PCR by using Allplex™ MTB/MDRe Detection kit to detect MTB from sputum specimens with a gold standard TB culture.

METHODS: A retrospective study design of adult patients (>15 years) with suspected pulmonary M. tuberculosis infection was conducted from January 2023 until October 2023, at Khon Kaen Hospital. The sample size was 101 cases. Sensitivity, specificity, accuracy, negative predictive value (NPV), and positive predictive value (PPV) of Allplex™ MTB/MDRe Detection, each with its respective 95% confidence interval (95%CI) were analysed and compared to MTB culture as the gold standard.

RESULTS: A total of 120 cases was included, and of these, 86 (71.6%) and 73 (60.8%) cases were diagnosed with pulmonary TB by Allplex™ MTB/MDRe and MTB culture, respectively. Sensitivity, specificity, and accuracy of Allplex™ MTB/MDRe for MTB detection were 97.3% (95%CI, 90.5-99.6), 68.1% (95%CI, 52.8-80.9) and 85.8% (95%CI, 78.3-91.5), respectively. The PPV and NPV were 82.5 % (95%CI, 75.7-87.8) and 94.1% (95%CI, 80.1-98.4). Positive (LR+) and Negative Likelihood Ratio (LR-) were 3.1 (95%CI, 2.0-4.6) and 0.04 (95%CI, 0.01-0.16).

CONCLUSIONS: The Allplex™ MTB/MDRe Detection kit is effective in detecting Mycobacterium tuberculosis to achieve standard treatment.