Rapid Skin Swab Test May Help Diagnose Parkinson’s
Test is quick and so are the results, UK researchers suggest
A non-invasive skin swab test may make a diagnosis of Parkinson’s disease in as few as three minutes, according to a study done at The University of Manchester in the U.K.
The test looks at samples of sebum, an oily matter made by glands in the skin, where it can detect changes in lipids (fats). Researchers used cotton swabs to sample sebum from people’s backs and found 500 compounds that were different between people with Parkinson’s and those without the disease.
While it is still early to bring the test into the clinic, the findings may be a step toward a more rapid diagnosis of Parkinson’s.
“We are tremendously excited by these results which take us closer to making a diagnostic test for Parkinson’s disease that could be used in clinic,” Perdita Barran, PhD, who led the study, said in a press release. Barran holds the chair of mass spectrometry in the Department of Chemistry at the university.
The study, “Paper spray ionization ion mobility mass spectrometry of sebum classifies biomarker classes for the diagnosis of Parkinson’s disease,” was published in the Journal of the American Chemical Society.
There is no single test to diagnose Parkinson’s. Doctors usually make a diagnosis by analyzing a person’s medical history and doing a full neurological examination. But a number of other diseases can cause symptoms similar to those of Parkinson’s. They require different treatments, so it is important to have a test that offers an accurate diagnosis.
People with Parkinson’s often experience skin problems, and some have oily or scaly skin that may itch or get inflamed. Barran’s team already knew that changes in sebum may help distinguish those with and without Parkinson’s.
The idea to test sebum for changes came up after a retired nurse named Joy Milne could notice changes in her husband’s smell some time before he was diagnosed with Parkinson’s at age 45. Milne has hyperosmia, which is an heightened sense of smell.
To find out what exactly what Milne was smelling that was different, the researchers designed a test that uses mass spectrometry — a tool that can identify compounds based on their weight and the charge of their ions — combined with paper spray ionization, which allows the direct analysis of compounds from paper.
Simply put, after swabbing a cotton tip over a person’s mid-back region, “the sebum is transferred to filter paper from sampling swab, and we then cut this to a triangle, add a drop of solvent, apply a voltage and this transfers compounds from the sebum into the mass spectrometer,” said Depanjan Sarkar, PhD, the study’s first author.
The study included a total of 150 people from 27 clinics across the U.K. There were 79 people with Parkinson’s with a mean age of 68.8 and 71 healthy (control) individuals who were a mean 5.2 years younger.
While age may change the amount of certain compounds in the body, it is unclear whether this stands true for sebum, the researchers noted.
The combined use of paper spray ionization and ion mobility separation allowed the researchers to detect 2.6 times more compounds than mass spectrometry alone, and it detected both light and heavier lipids. In total, they identified roughly 4,200 compounds from each person.
Difference in compounds
When the researchers compared the samples of sebum between people with Parkinson’s and those without, they found 500 compounds that differed in amount between the two groups. Some of the compounds were “only observed” in samples of sebum from people with Parkinson’s.
Two classes of lipids, called triacylglycerides and diglycerides, were present at significantly higher levels in the sebum of people with Parkinson’s than in that of people without the disease.
Testing of “each sebum sample is performed in [about] 2–3 [minutes], which is noticeably faster than current clinical mass spectrometry approaches,” the researchers wrote.
“This test has the potential to massively improve the diagnosis and management of people with Parkinson’s disease,” said Monty Silverdale, MD, PhD, one of the study’s authors.
Barran plans to continue her team’s work also through Sebomix, a spin-off company that she and her team, along with the University of Manchester, founded to develop and market sebum-based tests to diagnose Parkinson’s and other diseases.