Research: Superiority Of New Asthma Test Confirmed

Otago Researchers Confirm Vast Superiority Of New Asthma Test

- Nitric oxide breathalysing allows accurate, quick, and easy diagnosis-

World-first research at the Dunedin School of Medicine which compares new asthma diagnosis technology with conventional tests could revolutionise asthma diagnosis guidelines internationally, researchers believe.

Results of the study just published in the American Journal of Respiratory and Critical Care Medicine – the world’s leading respiratory medicine research journal - confirm that the new technology is “superior to any of the conventional tests currently used by doctors to diagnose asthma”, says lead author Associate Professor Robin Taylor.

The new technique involves a 10 minute ‘breathalyzer test’ that measures exhaled nitric oxide. Levels of this gas are increased in the breath of patients with asthma and its presence can be used to distinguish asthma from other respiratory conditions, says Professor Taylor, principal investigator of the Otago Respiratory Research Unit. Increased levels of nitric oxide in the breath also occur in patients whose asthma is poorly controlled or inadequately treated, he added.

“Nitric oxide technology was developed in the mid 1990s. We have now applied the technique in the clinical setting. We recently offered the test to GPs in Dunedin who wanted to know whether a patient with cough or wheeze or shortness of breath might have asthma - or some other condition,” he says.

Results in 47 patients showed that compared with all the other conventional tests used to sort out the diagnosis, exhaled nitric oxide measurements were the “most accurate and also the simplest to carry out”, he says.

“Sometimes GPs consider a diagnosis of asthma but are not quite sure. That’s because the same symptoms occur in a range of other conditions such as bronchitis or post-viral bronchial irritation, as well as with asthma. But it is important to know the difference because that influences decisions about treatment - this test lets GPs know that they have got it right. Previously it has been much more of a hit or miss exercise.”

“There has been immense interest in our results from researchers and clinicians in a number of countries. This is a very significant step forward. Asthma is common, but so are other respiratory conditions. It is important to get the diagnosis right.”

Nitric oxide analysers are not yet widely available in New Zealand, but based on the Otago findings it is likely that the new technology will be introduced into clinics and hospitals in major centres over the next two to three years, he says.

Members of the Dunedin research team are also continuing their studies in this area to look at whether exhaled nitric oxide levels can be used to guide GPs about how much “preventer” medication to use to treat asthma, he says.

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