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Scientists at work on low-cost test for tuberculosis

Recent WHO recommendation about TB testing prompted by team’s finding.


A team of researchers led by McGill University epidemiologist and tuberculosis expert Madhukar Pai is working on a new low-cost test for diagnosing the deadly disease that continues to afflict much of the developing world.

“There are 9.5 million new TB infections every year,” Dr. Pai said. “Most countries are unable to detect 65 percent of all cases. Every undiagnosed or misdiagnosed case will result in spreading the infection to 15 other people. So this is definitely driving the epidemic.”

Dr. Pai made headlines in August when a research paper he co-wrote was influential in prompting the World Health Organization to issue a policy statement recommending that blood tests should not be used to diagnose tuberculosis. Dr. Pai’s paper concluded that the tests, although widely used in private clinics in many developing countries, have only a 50-percent accuracy rate – no better than a coin flip.

Having helped discredit the tests, Dr. Pai is now working to fill the gap. In May he received a $100,000 Grand Challenges grant to develop a more accurate replacement. The Grand Challenges grant program is run by a federally funded non-profit organization and funds research initiatives addressing global health problems.

Dr. Pai and his team will work to develop a simple “dipstick” test for extrapulmonary tuberculosis – the 20 percent of TB that attacks organs other than the lungs. They want to design the test so that it is easy and inexpensive to produce in India, the most TB-burdened country in the world. The device, if successful, will consist of a plastic cartridge with a membrane containing biomarkers – antibodies, antigens or proteins associated with the disease.

Although accurate diagnostic tools are available in developing countries, they are costly. There is a dire need for cheap, accurate and fast tests. “This diagnostic tool would cost a dollar or two, and would be as easy as a pregnancy test,” Dr. Pai said. “You would extract a drop of spinal or abdominal fluid from a person, place it in the device and, within a few minutes, get a read-out with an accurate diagnosis.” But he characterized the research as a high-risk venture: “I don’t know yet if it will work.”

Some remote areas of Canada are also afflicted with the disease. In July, Dr. Pai received $355,000 from the Canadian Institutes of Health Research to conduct a feasibility and cost-effectiveness study to determine whether inexpensive DNA-based lab tests for tuberculosis could be implemented in Nunavut, the only area in Canada currently suffering from an outbreak of the disease.

“We need to learn whether these tests will work in that remote environment, and if they will be cost effective and reduce delays in diagnosis,” Dr. Pai said. “We are really in a race to try to stop this epidemic.”

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