New Test To Detect Dangerous Stage Of TB
Researchers are testing a new strategy to effectively detect the dangerous stage of TB in Pakistani children for the first time.
Asian Scientist (Aug. 22, 2013) – More than 20,000 people in Pakistan are being tested for the potentially deadly stage of tuberculosis (TB) using a new strategy to effectively detect the disease in children for the first time.
At least 600 million people in Pakistan, India and Bangladesh are infected with the TB bacterium Mycobacterium tuberculosis. Each year at least three million people reach the potentially deadly stage called active TB.
The condition is treatable with antibiotics, but conventional tests inevitably miss more than one out of three active cases. About 400,000 die from the disease in South Asia every year.
The new TB screening strategy looks for tell-tale antibodies in the blood that are found only when a person is fighting off active TB.
In conventional screening, a laboratory worker must identify the bacterium in a sputum sample observed under a microscope.
This century-old test rarely picks up more than 50 percent of active cases of lung TB but the new antibody test is expected to detect about 80 percent of active cases.
The new test requires a few drops of a blood sample and takes two hours to provide results, while the sputum microscopy test requires three sputum samples collected over three days. The speed of the antibody screening means that many millions more people could be screened worldwide per year, according to researchers.
The new strategy is based on an FDA-approved diagnostic instrument. Its application to detect TB antibodies was developed by scientists in the United States in collaboration with their colleagues in Pakistan.
The results of preliminary trials using this diagnostic instrument for detecting active TB were reported in Clinical and Vaccine Immunology.
According to the researchers, the initial cost of the antibody testing machines are higher than current assays but the technology allows for so many more people to be tested. So the cost per patient would be about the same when used on a large scale.
In the Pakistan trial the machine will be shared by at least three hospitals in different regions of the country, and patients will come to the hospitals to provide blood samples.
But if put to full use, the system is designed to test blood samples taken in rural clinics, dried on filter paper and mailed to a major urban hospital.
The article can be found at: Ravindran et al. (2013) Exploratory Study On Plasma Immunomodulator And Antibody Profiles In Tuberculosis Patients.
Source: UC Davis; Photo: DFID – UK Department for International Development/Flickr/CC.
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