MTB RIF in Dehradun

What is a MTB RIF?

This is a cartridge-based molecular test that does two jobs on one sample in about two hours. It detects the DNA of Mycobacterium tuberculosis, confirming active tuberculosis with far greater sensitivity than microscopy of a smear, and simultaneously identifies mutations in the rpoB gene that confer resistance to rifampicin. That second capability is what transformed tuberculosis care in India. Rifampicin is a backbone drug of standard first-line treatment, and resistance to it is the accepted marker for multidrug-resistant tuberculosis, which needs a completely different, longer and more toxic regimen. Before this test, resistance was established by culture, which takes weeks, during which a patient could be taking a regimen that was never going to work while remaining infectious. The result is available the same day. It is important to be clear about what it is not: it detects bacterial DNA, alive or dead, so it cannot be used to judge whether treatment is working in someone already being treated, and a negative result in a strongly suspicious case does not exclude tuberculosis, particularly in extrapulmonary disease where the organism load is low.

Why take this test?

This test is advised where active tuberculosis is suspected: a cough persisting beyond two to three weeks, fever particularly in the evenings, drenching night sweats, unexplained weight loss, blood in the sputum, or an abnormal chest X-ray. It is the recommended first diagnostic test for presumed pulmonary tuberculosis in India rather than smear microscopy alone, because of its higher sensitivity and the resistance information it provides. It is equally valuable in extrapulmonary disease, where it can be run on lymph node aspirate, pleural or ascitic fluid, cerebrospinal fluid and other specimens, though sensitivity is lower there. It is particularly important in anyone previously treated for tuberculosis, in contacts of a known drug-resistant case, and in people living with HIV, all of whom carry a higher risk of resistant disease. Tuberculosis is a notifiable disease in India and treatment is available free through the national programme; a positive result should go to a doctor immediately.

• Cough persisting beyond two to three weeks
• Evening fever, night sweats or unexplained weight loss
• Blood in the sputum, or an abnormal chest X-ray
• Suspected extrapulmonary tuberculosis on fluid or tissue samples
• Previous tuberculosis treatment, raising the risk of resistance
• Contact of a known drug-resistant case, or HIV co-infection

FAQs: MTB RIF in Dehradun