Vidyya Medical News Service
Volume 6 Issue 102 Published - 14:00 UTC 08:00 EST 11-Apr-2004 Next Update - 14:00 UTC 08:00 EST 12-Apr-2004
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A simple breath test could detect tuberculosis

Coughing into a breathalyzer could be the new way to detect the most common form of tuberculosis. Rapid Biosensor Systems had developed a portable device that would be quicker and easier to use than the current screening method, called the Heaf test.

The Heaf test involves an injection of tuberculin into the skin. The patient has to wait one week to see if a reaction develops, which would indicate exposure to infection. Tuberculin is a fluid containing the products formed by the growth of the bacterium which causes TB.

The Rapid Biosensor system can deliver 90% accurate results in under 10 minutes. The breathalyzer is also disposable, cheap and has the potential to screen for other diseases, although it cannot be used as a diagnostic tool. It can also be used by someone with no formal medical training.

The breathalyzer works through an optic sensor which sits inside the tube. This sensor has a coating designed to attract bacteria. When the patient coughs into the tube, sputum is brought up - a secretion produced in the lungs where tuberculosis can reside. If TB is present in the lungs, it will stick to this optical sensor, giving a positive reading.

The device is currently under clinical trial in the UK and in India. Rapid Biosensor hopes to apply for a company licence by May this year.

A spokesperson for TB Alert, a tuberculosis awareness charity, said: "We would like faster, simpler methods of diagnosis." At the moment a patient has to be seen twice and that already leads to complications. Furthermore, if the test does show infection, then the patient has to be properly diagnosed, which involves an X-ray or sputum analysis."

However Dr Kate King, at Cambridgeshire and Peterborough Health Protection Unit said that as the breathalyzer could only test for one type of TB, it was unlikely it could entirely replace the current screening method. She said around one third of tuberculosis cases involved infection in other organs, such as kidneys, lymph nodes, brain tissue, bones and joints.

"This new device has potential value to people who have tuberculosis in their lungs," she said. This is the only form of the disease that is infectious, and people with it will be sicker than those with tuberculosis infection elsewhere."

The rate of tuberculosis has steadily risen in the UK over the past 17 years, increasing by 34% since 1987. In 2002 almost 7,000 people contracted the disease.

Globally, around 8 million people contract TB each year, and two million will die as a result. In 1993, the World Health Organization declared tuberculosis a 'global emergency'.

The classic symptoms of TB are lung infection, chronic cough that lasts for weeks, fever, night sweats and weight loss. it can also infect the lymph nodes and kidneys.

Tuberculosis can lie dormant in a person for years and then strike when the immune system is weak.

Most cases can be treated with a six-month course of antibiotics.

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