Bangalore: Scientists at the International Centre for Genetic Engineering and Biotechnology (ICGEB) in New Delhi have shown that tuberculosis may be diagnosed in future using a fast, inexpensive urine test.
Their test reported in the American Chemical Society (ACS) journal Analytical Chemistry can also be used to monitor the effectiveness of treatment for tuberculosis which is on a rampage in the developing world, the ACS said in a statement.
Currently healthcare workers diagnose the disease by identifying the TB bacterium in sputum or blood samples. But these tests tend to be time-consuming, sometimes taking days or weeks to give results. The tests also require the use of specially trained personnel or expensive equipment that might not be available in some areas.
In their report, ICGEB scientists led by Virander Singh Chauhan and Ranjan Kumar Nanda describe an advance toward a test that overcomes these drawbacks.
They analyzed so-called volatile organic compounds (VOCs) - substances that evaporate easily in the air - present in the urine of TB patients and compared them with VOCs in the urine of healthy patients. The scientists found that infection with TB produces a distinct pattern of certain VOCs in much the same way that distinct fingerprint patterns can identify individuals.
Identification of these patterns sets the stage for developing a portable "electronic nose" that can quickly sniff urine samples to detect TB, the scientists suggest.
ICGEB scientists said they used for their study urine samples from subjects presenting with cough for more than three weeks in the outpatient department of Lala Ram Sarup Institute of Tuberculosis and Respiratory Diseases, New Delhi.
"Among numerous volatile molecules present in urine samples, the levels of five VOCs were found to be significantly altered and together form a molecular signature that can accurately discriminate TB patients from non-TB individuals. We have demonstrated the potential of urinary VOCs as a TB disease marker," the researchers said in their paper.
They said a major advantage of the proposed method is the non-invasive nature of urine collection. "Urine is a comparatively safer matrix as compared to sputum and painless in collection as compared to blood."
TB strikes an estimated 10 million people and kills three million each year, mostly in developing countries, the scientists noted.
Funding for their study was provided by the government of India`s Department of Biotechnology and International Centre for Genetic Engineering and Biotechnology.
According to WHO, each year nearly 20 lakh people in India develop tuberculosis, of which 8.7 lakh are infectious cases. It is estimated that annually around 330,000 Indians die of the disease. The country accounts for one fifth of global tuberculosis cases.