ID’ing TB

By John Pastor • Published: October 30th, 2013
Category: Health in a Heartbeat

Score one for the doctors and scientists battling the spread of one of the world’s most dangerous infections … TB.

Short for tuberculosis, TB is a contagious lung disease that annually kills about 1.8 million people, mainly because detection rates are low and ever-so slow.

It’s not easy to I-D TB.

Health-care workers diagnose the disease with a combination of two tests that have been in use for a century. First, a sample of phlegm from people with respiratory infections is stained with dyes that adhere to TB bacteria. If the secretions appear to harbor TB, a separate sample is taken to a laboratory and placed in a container called a culture, where the germs can grow and be identified.

The method is time-tested … and time-consuming, typically taking two weeks or more to confirm an infection.

This explains doctors’ excitement about a new test to diagnose TB in children. The test delivers results practically at the point of treatment, bypassing the lengthy lab work.

It works with only disposable cartridges to capture fluids and a personal computer for analysis.

In a National Institutes of Health study of nearly 400 children at a primary care clinic in South Africa, the new method took only a few hours to identify about two-thirds of the infections that were detected weeks later by culture tests.

It also picked up on five times as many potential cases of TB as the dye-and-microscope test.

Doctors are encouraged by the results, because children have lower levels of TB bacteria than adults, making them much more difficult to diagnose. Even children with drug-resistant TB were identified.

The promise of the new test is to quickly treat children in health-care settings that may not have a lot of resources.

It won’t even humankind’s score against one of the world’s greatest scourges. But it gets us closer.