Researchers from University College London and King’s College London in the UK have developed a device that can measure stress hormone cortisol from ear wax samples.
“Cortisol sampling is notoriously difficult, as levels of the hormone can fluctuate, so a sample might not be an accurate reflection of a person’s chronic cortisol levels. Moreover, sampling methods themselves can induce stress and influence the results.” says Dr Andres Hernane-Vives, lead researcher behind the device.
“But cortisol levels in earwax appear to be more stable, and with our new device, it’s easy to take a sample and get it tested quickly, cheaply and effectively.”
While cortisol has been considered a possible biomarker for depression, difficulties in accurately measuring it mean that it has not yet gained this status. So far, the most common way to measure cortisol levels is via hair samples, which are subject to short-term fluctuations.
The researchers' new wax-sampling device is similar to a cotton swab but with a brake to prevent it from venturing too far into the ear canal. In their pilot study, the researchers tested the device on 37 study participants alongside other cortisol-measuring techniques, including hair and blood samples.
All in all, they found that wax samples yielded more cortisol than hair samples and that the new technique was faster and cheaper to conduct than existing methods. They also found that measures of cortisol from earwax were the least influenced by stressful events and alcohol consumption and that participants rated the new self-sampling device as more comfortable than existing methods.
As such, Dr. Hernane-Vives is now setting up a company, called ‘Trears’, to bring the device to market. He and his research team are also investigating whether the device could also be used to measure glucose levels from earwax samples to monitor diabetes.