image copyrightPARKINSON'S UKimage captionDaxa Kalayci was misdiagnosed several times
A simple skin-swab test could be used to help diagnose the degenerative brain condition Parkinson's disease, UK scientists say.
Studies with volunteers show it can quickly detect tell-tale compounds in sebum – the oily substance that protects the skin.
People with Parkinson's can have higher than usual concentrations of these.
Researchers discovered this after a woman amazed doctors with her ability to detect Parkinson's through smell.
Retired nurse Joy Milne, 68, from Perth, noticed the "musky" smell on her husband, Les, years before his Parkinson's diagnosis.
She has been helping scientists at the University of Manchester explore the link.
And a blinded test of her odour-detecting skills found she was 100% accurate.
media captionJoy Milne can smell Parkinson's disease before it is medically diagnosed
The research team moved on to using a mass-spectrometry machine to detect the compounds.
And they now have data from 500 people, showing the skin test can correctly distinguish those with Parkinson's more than eight out of every 10 times.
Investigator Prof Perdita Barran said: "We believe that our results are an extremely encouraging step towards tests that could be used to help diagnose and monitor Parkinson's.
"Not only is the test quick, simple and painless but it should also be extremely cost-effective because it uses existing technology that is already widely available.
"We are now looking to take our findings forwards to refine the test to improve accuracy even further and to take steps towards making this a test that can be used in the NHS and to develop more precise diagnostics and better treatment for this debilitating condition."
Currently, there is no cure and no definitive test for Parkinson's.
And diagnosis can take years.
The researchers are seeking funding to further develop their test, which they believe could also help track disease progression and measure whether treatments are having an impact, at the molecular level.
Their latest work, published in the journal Nature Communications, suggests progression of the disease comes with changes in the regulation of lipids in cells.
Daxa Kalayci, 56, of Leicester, was misdiagnosed several times over four years before finally finding out she had Parkinson's in 2019.
"I was misdiagnosed with anxiety, stress-related tremors and told that my problems stemmed from going through the menopause," she said.
"Despite my diagnosis eventually being confirmed… a quick and simple diagnostic test for Parkinson's would have given me the chance to start my treatment earlier and enjoy life a lot more.
"But instead, I lost so many years not being able to pursue a career as a paramedic or go back to nursing.
"This test could be a game-changer for people living with Parkinson's and searching for answers, like I was."