Simple Blood Test to Diagnose People With Active Tuberculosis

Tuberculosis (TB) a disease that globally infects 9.6 million people each year and kills 1.5 million. A simple blood test that can accurately diagnose active TB has been developed by a team of US researchers, including an Indian-origin scientist.

Researchers at the Stanford University in California have found a gene expression that distinguishes patients with active TB from those with either latent TB or other diseases.

Tuberculosis - Spread - Symptoms - Diagnosis - Treatment - FAQs
Tuberculosis, caused by Mycobacterium tuberculosis, primarily affects the lung. It may spread to other organs.

‘A simple blood test that can not only diagnose active tuberculosis accurately, but can also study the effectiveness of different treatments has been developed by researchers.’

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"The test can be used not only for diagnosis and to inform treatment, but also to study the effectiveness of different treatments. The test’s hugely accurate negative response would be especially helpful in monitoring the effectiveness of treatments during clinical trials," said Purvesh Khatri, assistant professor at the university.

Named as the Khatri test, it works on an ordinary blood sample and removes the need to collect sputum - a common test for TB.

The results showed that the test could also signal a TB infection even if the individual also has human immunodeficiency virus (HIV).

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Patients with tuberculosis should eat a healthy diet so that they build up their immunity to fight against tuberculosis.

The test won’t give a positive response if someone only has latent TB or has had a TB vaccine. The test is 86% sensitive in children it works in adults too.

And if the test comes up negative, it’s right 99% of the time. That is, of 100 patients who test negative with the Khatri test, 99 do not have active TB, the researchers elicited.

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Extra pulmonary tuberculosis is infection of tissues and organs other than the lungs by mycobacterium tuberculosis and related organisms.

Further, the test can potentially be done under relatively basic field conditions in rural and undeveloped areas of the world.

"Any hospital should be able to perform the test. Villages without electricity could likely use ordinary blood samples and a solar-powered PCR machine, which multiplies strands of DNA, to accurately test people for active TB," Khatri mentioned.

Screening Tests for Tuberculosis
Tuberculin skin test and Interferon – Release Assays are tests used to screen for tuberculosis.

Khatri’s team identified three human genes whose expression changes in a consistent pattern, revealing the presence of an active tuberculosis infection.

The team validated the new three-gene test in a separate set of 1,400 human samples from 11 different data sets, confirming the diagnostic power of the test.

Source-IANS