Breath tests for diseases

Dr Masood Yousef is using GCMS-TD (gas chromatography, mass spectrometry and thermal desorption) technology to develop a breath test for diagnosing diseases including diabetes and cancer.

Dr Yousef, a senior research assistant in the Welsh Centre for Printing and Coating, is using GCMS-TD to analyse concentrations of volatile organic compounds (VOCs) in breath.

‘Studies have shown that high concentrations of certain VOCs in breath can correlate with disease,’ said Dr Yousef. ‘For example, the odour of ‘pear drops’ esters and acetone in relation to diabetes, ammonia in relation to hepatitis, and dimethyl sulphide to cirrhosis. There are also certain compounds that seem to mark out particular types of cancer.

‘If unique markers for specific diseases can be recognised earlier than traditional techniques, then there is immense potential to revolutionise early disease diagnosis before any symptoms have developed, and without the need for invasive procedures.’

The system works by analysing all the component chemicals and compounds that make up a patient’s breath. The GCMS-TD creates a breath profile, which allows scientists to identify volatile organic compounds that may signify the presence of disease.

Diagnostic techniques based on exhaled breath are said to be much less developed than traditional blood or urine analysis techniques, and are not widely utilised in clinical practice. Such techniques have also previously been seen as crude, subjective and unreliable.

However, due to improved analytical methodology, volatile marker-based diagnostics offers new potential in the rapid diagnosis and monitoring of illnesses.

Dr Yousef believes that the breath test will provide a more convenient and rapid method for diagnosing serious diseases than blood or urine analysis, and will require minimal medical intervention.

He said: ‘Breath samples are much easier to collect than blood and urine, for the patient as much as for the person collecting the sample. They can be collected anywhere by people with no medical training, and there are no associated biohazard risks.

‘Overall, the procedure is likely to be much more cost effective than conventional methods, potentially saving the NHS a great deal of time and money.’

The research could lead to the development of simple diagnostic tools such as test strips that give positive results for specific illness markers, thereby reducing the cost and level of expertise for diagnosis.

The GCMS-TD equipment has been funded by a grant from the Welsh Assembly Government Knowledge Exploitation Fund. It was originally used to research the level of solvents and other VOCs inhaled by operators of printing machinery.