Computerised nose imitates ancient Chinese sense for scents to diagnose infections

Cranfield 08 October 1999Scientists at the British Cranfield University have developed a new medical test based on ancient Chinese methods for diagnosing disease. The sensor named "Diag-Nose", uses olfactory-emulating technology to "sniff out" illness. A number of medical conditions produce a characteristic odour, and their identification is a difficult process due to the subjective nature of human smell. To solve this problem, Dr. Selly Saini and Jan Leiferkus of the Cranfield Postgraduate Medical School in Bedfordshire, have developed an artificial nose that electronically identifies odours. It uses the same process as human noses except odours are classified electronically, thereby avoiding human bias. The technology will dramatically reduce the diagnosis time for Urinary Tract Infections (UTIs).

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The Diag-Nose device is fitted with a range of electronic sensors tuned to particular chemicals, akin to human smell receptors. If traces of the chemical are present, the sensors send a message to the machine's brain. In fact, this brain forms a neural network, trained to associate certain smells with particular events, in this case the presence of infectious bacteria. UTIs are second in incidence only to respiratory infections and rank first amongst adult bacterial diseases requiring medical attention. The majority of sufferers are women as the female urethra is shorter than that of the male. By the age of thirty, 20% will have suffered a UTI with many having recurrent episodes. The most common complaint affecting the bladder is cystitis, more serious complaints can go on to affect the kidney.

Traditional lab tests, which grow a culture from a swab or urine sample, take between 24 and 48 hours. Faster, more efficient diagnosis and treatment not only eases the pain and discomfort experienced by patients but may free up many medical resources. The Diag-Nose delivers its results in only six hours and can be installed in most surgeries. The new test can also be done for a fraction of the present cost of UTI diagnosis. The test works by sniffing out characteristic odours of infecting micro-organisms from the patient's urine when it is mixed with a specially engineered growth medium. As the micro-organisms multiply, they produce odours which give their presence away. Each micro-organism produces a different odour allowing the Diag-Nose to determine the underlying infection, so correct treatment can be given.

Laboratory trials for the new test have proved very successful and already 80% of UTIs can be detected. Clinical trials starting shortly will give a full evaluation of Diag-Nose. Initial trials showed that the Diag-Nose prototype was 100 percent accurate. Currently, diagnostic companies are being sought to bring the technology to the market. Dr. Saini believes that if clinical trials prove successful, Diag-Nose will hold a number of advantages to patient and doctor. Since the test only requires a small urine sample, it becomes much more comfortable for the patient. It reduces the diagnosis time allowing same day treatment and less anxiety for the patient. Diag-Nose is equally being evaluated as a means of diagnosing diseases such as tuberculosis, asthma, as well as certain bowel cancers and infections in wounds.

The Cranfield researchers at the Centre for Analytical Science are confident the Diag-Nose device will eventually fit on a desktop and will cost less than $3000. Dr. Selly Saini is convinced that this technology some day might be adapted to create a smart bandage which can detect if a wound has become infected, and he adds that in the past, the Chinese have done a lot of work in using the sense of smell to diagnose disease. In Asia, a patient suspected of having tuberculosis used to spit into a fire, which gave off a distinctive smell. The Cranfield University has a track record in developing tools for medical diagnosis, according to Dr. Saini, who stresses that a popular home glucose testing kit for diabetics was designed here. You can also read the article on breath-smelling electronic noses in this very same issue.


Leslie Versweyveld

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