Thursday, June 21, 2007

1-minute test to detect TB

Tuberculosis diagnosis may soon take just one minute.

Thai scientists from Srinakharinwirot University's nanotechnology centre are close to developing a new technology with the help of bio-sensors that will diagnose micobacterium tuberculosis within 60 seconds.

According to associate professor Kosum Chansiri, the new technique will be a breakthrough as present day testing methods like culture and polymerase chain reaction (PCR) are time consuming and unable to determine accurately if the TB strain is resistant to any drug. While private hospitals in India use PCR, the country's National TB Control Programme still believes in the sputum microscopy test that takes over two days.

Dr L S Chauhan, chief of India's TB control programme, said, "Rapid diagnostic tools are much needed in India which sees 18 lakh fresh cases of TB every year. The present day PCR test isn't specific and the sputum test takes two days for results to show." Soumya Swaminathan from the Tuberculosis Research Centre, Chennai, however, said she was sceptical. "Scientists are working on biosensors that are ideal for TB. But till now, there are no bio-markers that are specific for TB."

Biosensor is a technology in which enzymes or antibodies are used to detect sugars and proteins in body fluids, contaminants in water and gases in air.

The most widespread example of a commercial biosensor is the blood glucose biosensor, which uses an enzyme to break blood glucose down. Scientists are widely using biosensors for several medical targets glucose monitoring in diabetes patients, detection of pesticides and river water contaminants, remote sensing of airborne bacteria, detection of pathogens, routine measurement of folic acid, biotin and Vitamin B12.

The Thai announcement comes after Rapid Biosensor Systems, a Cambridge-based developer, recently announced the creation of a TB breathalyzer, a portable device that will detect TB in less than 5 minutes. Clinical trials of this technology are about to start in the UK and India. Dennis Camilleri, the chief executive officer of RBS, had said, "Our test is very fast. You simply cough into a tube. If TB bacteria are present in the breath sample then they bind to a special fluorescent bio-coating that has been applied to an optical prism inside a collection tube. Analysis of the fluorescence signal indicates if TB is present." Camilleri said because the system does not require samples to be sent to a lab for analysis, it could potentially be used at airports and seaports to screen people as they enter a country and also enables the screening to be done "while you wait". So people with positive TB screening results can be isolated immediately.

Courtesy : The Times of India (21-06-07)

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