Telethon Kids Institute researchers are urging caution in the use of a widely accepted test for diagnosing asthma, after their study found it may not be accurate in some settings.
The cost effective and easy to use mannitol challenge test is recommended for diagnosing asthma in individuals who have asthma symptoms and in whom asthma is suspected, with a positive test being used to confirm a diagnosis of asthma.
More recently the mannitol test is being recommended to screen for asthma in defence force recruits, firefighters and athletes, and use of the test outside the traditional medical setting is predicted to increase.
However, in a study published in the journal Respirology, Telethon Kids researchers found that a positive result may not predict the presence of asthma when used outside a medical setting.
The researchers, testing participants from the Western Australian Pregnancy Cohort (Raine) Study, found a positive test predicted a diagnosis of asthma when used on participants who reported asthma symptoms, but was not reliably correlated with an asthma diagnosis in those participants without symptoms suggestive of asthma.
"We found that when the mannitol test is applied to groups that have symptoms suggestive of asthma, it's actually a really useful tool with a high correlation between positive test and a diagnosis of asthma," lead author Elisha White said.
"However, when the mannitol test is used in non-clinical groups (those who have no symptoms of asthma), a positive test is no longer correlated very highly at all with an asthma diagnosis."
"Interestingly, we found that in the broader population of Raine participants, a negative mannitol test was good at excluding asthma."
"This is really important to know because when this test is used in these non-clinical groups, like defence force recruits, it may lead to a wrong diagnosis of asthma. This means that we need to ensure we use the test results in the correct way."
Supervising author Professor Graham Hall said it was important that a mannitol test result wasn't used to diagnose asthma in isolation.
"It's very important that we take into account the whole clinical picture of the patient when confirming or excluding a diagnosis of asthma," Professor Graham Hall said.
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Media contact:
Jasmine Raisbeck, Senior Communications Officer, Telethon Kids Institute
08 9489 7635 or 0437 575 875 or jasmine.raisbeck@telethonkids.org.au
About Telethon Kids Institute:
The Telethon Kids Institute is one of the largest, and most successful medical research institutes in Australia, comprising a dedicated and diverse team of more than 500 staff and students.
We've created a bold blueprint that brings together community, researchers, practitioners, policy makers and funders, who share our vision to improve the health and wellbeing of children through excellence in research.
The Institute is headed by leading paediatrician and infectious diseases expert Professor Jonathan Carapetis, with Founding Director Professor Fiona Stanley now Patron.
Telethon Kids is independent and not-for-profit. The majority of funding comes from our success in winning national and international competitive research grants. We also receive significant philanthropic support from corporate Australia and the community.