US scientists have developed an electronic nose device for diagnosing respiratory infections.
E-nose could detect bacterial infections
It works by comparing "smell prints" from a patient's breath with standardised readings.
The doctor can then tell whether the patient has a bacterial infection and allow antibiotics to be prescribed correctly.
The University of Pennsylvania team say the device is faster, cheaper and easier to use than current methods.
It can be difficult to distinguish common respiratory infections, such as pneumonia.
This can mean that antibiotics are prescribed incorrectly.
The researchers say their new device could help prevent this.
How it works
All bacteria produce unique mixtures of exhaled gas, much like people have unique fingerprints.
The e-nose recognises and identifies these patterns. This information can then guide whether an antibiotic is appropriate and, if so, which one.
Dr Erica Thaler and colleagues have tested the device in three trials with success.
The first two studies looked at pneumonia cases among patients who were on ventilators in a surgical intensive care unit. The e-nose effectively diagnosed 92% of pneumonia cases among 25 patients and distinguished 13 positive cases from 12 other patients who did not have this infection.
The third looked at sinusitis - a common infection found in outpatient clinics. The e-nose effectively diagnosed 82% of cases among 22 patients, half with the infection and half without.
Dr Thaler said the device could radically change and improve the way both conditions are diagnosed.
"And given that we can apply this sensory analysis to the detection of pneumonia and sinusitis, the, hopefully, it can be applied to common bacterial infections of the upper respiratory tract," she said.
Professor Andrew Peacock, of the British Thoracic Society, welcomed the concept.
"Lung specialists are commonly faced with a chest x-ray showing changes which could represent infection, tumour, fluid or a number of other causes. If we could quickly and accurately diagnose infection from a computerised 'sniff', this would indeed be an advance."
But he added: "Obviously there will need to be further research in to the technology."
More than lungs
The e-nose is also being studied for its possible use in diagnosing other conditions such as lung cancer and liver and kidney diseases.
It might be possible to detect chemicals and biological agents with the device.
The study findings were presented at the combined annual meetings of the Triologic and the American Broncho-Esophagological Association in April.