Is a positive PCR test confirmatory for TB?
Q: I am 32 years old. I underwent a test called PCR for M. Tuberculosis, prescribed by the doctor, as I couldn't conceive the 2nd time. The result of the test is positive. What does it mean? What is this test and what is the treatment?
A:You have not mentioned the sample which was tested, and your symptoms, and why the test was done in the first place. The gold standard for diagnosis of tuberculosis is demonstration of mycobacteria from the clinical sample. This is often not possible in certain cases which have a low bacterial load. Significant improvements in understanding of molecular biology of Mycobacterium tuberculosis has led to development of newer diagnostic techniques for tuberculosis, and Polymerase chain reaction (PCR) is an emerging diagnostic tool for diagnosis of TB. However, its role in day-to-day clinical practice is not completely clear. A negative PCR never eliminates possibility of tuberculosis, and a positive result is not always confirmatory.