Real-Time Polymerase Chain Reaction Assay for the Diagnosis of Pulmonary Tuberculosis

Real-Time Polymerase Chain Reaction Assay: A Response to Recent Letter to the Editor

“…As a response to the issues of false-positivity raised by Wiwanitkit 1 , it was mentioned in our paper 2 that "In our study, the false-positive rate was 0.5% in sputum and 2.0% in bronchoscopic aspirates. False-positivity in PCR has been reported to be due to carry-over contamination between specimens, cross-reactions with isolated nontuberculous mycobacteria, or dead tissue debris from previous TB scarring in highly endemic areas."…”

“…Thank you for the recent comments 1 for the topic of real-time polymerase chain reaction (RT-PCR) assay 2 . We propose that positivity in RT-PCR using any respiratory specimens suggests the possibility of active tuberculosis (TB) in clinically suspected cases, guiding to start anti-TB medication, and RT-PCR from selective bronchoscopic aspirates enhances the diagnostic yield much more when added to sputum examination 2 .…”

“…We propose that positivity in RT-PCR using any respiratory specimens suggests the possibility of active tuberculosis (TB) in clinically suspected cases, guiding to start anti-TB medication, and RT-PCR from selective bronchoscopic aspirates enhances the diagnostic yield much more when added to sputum examination 2 . Wiwanitkit 1 mentioned that "There are some concerns on this assay. False-positive of the test can be seen in cases with treated or old lesion from pulmonary TB and the low sensitivity of the test can be seen."…”