National Physical Laboratory

Breath monitors independently verified


Image courtesy of iStockphoto
Image courtesy of iStockphoto

NPL worked with a medical diagnostic company, Bedfont Scientific Ltd, to help them independently verify their breath monitoring sensors.

Trevor Smith, Managing Director of Bedfont, was seconded to NPL under a scheme called Measurement for Innovators (funded by the National Measurement Office) so that Bedfont could test their instruments against concentrations of carbon monoxide and hydrogen in concentrations that are relevant to the medical market.

Bedfont's personal diagnostic gas sensors can continuously monitor levels of certain gases in human breath, and can be used in place of certain invasive blood tests.

In order to extend their position in this market sector, and confirm their reputation for quality and accuracy, Bedfont required its instruments to be evaluated against an alternative technique.

NPL assisted the company in determining some key performance parameters for two types of electrochemical breath sensors, one for measuring carbon monoxide, and the other for hydrogen. The test results provided Bedfont with an independent verification of their sensors, potentially giving an edge over their international competitors, with the opportunity to expand into other global markets and within the UK's National Health Service (NHS).


Bedfont Scientific Ltd, a UK company based in Kent, are one of the market leaders in developing personal diagnostic gas sensors for the medical market.

In order to extend their position in this market, and confirm their reputation for quality and accuracy, Bedfont needed its instruments to be evaluated independently.

To achieve this, they contacted NPL and arranged for one of their staff members to work at NPL under a National Measurement System secondment scheme. This gave Bedfont first-hand access to NPL's scientific expertise and state-of-the-art facilities.

Following the secondment, Trevor Smith of Bedfont commented, "It was very important for us to be able to show that our instruments are fit for purpose, and scientifically sound. NPL helped us demonstrate this by revealing the close agreement between analytical techniques of gas analysis, traceable calibration standards, and our breath monitoring equipment."

NPL helped Bedfont determine some key performance parameters for two types of electrochemical breath sensors, one for measuring carbon monoxide, and the other for measuring hydrogen. The presence of certain levels of these gases in human breath are medically important as they can indicate whether a patient is smoking (it's helpful for healthcare workers to demonstrate potentially harmful carbon monoxide levels to smokers as it can encourage them to stop smoking), or suffering from a gut disorder (indicated by increased levels of hydrogen in a patient's breath).

Out of the Bedfont products tested, NPL confirmed that they measured their target gases accurately, had linear and reproducible response characteristics, and had negligible interferences from other breath gases, which may cause false positives.


Results of the tests carried out at NPL provided Bedfont with the independent verification of their sensors that they needed. This should help Bedfont compete in the global healthcare market, and it demonstrates to Bedfont's customers that their products will do the job they expect.

"Working with NPL has been an excellent experience and one we would like to develop in the future with more of our products" - Trevor Smith, Managing Director, Bedfont Scientific Ltd

For more information, please contact Nick Martin

Find out more about NPL's Chemical Metrology research.

Find out more about NPL's work in the Healthcare sector.

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Last Updated: 16 Apr 2012
Created: 22 Dec 2010


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