Blood test for chronic fatigue syndrome developed

Scientists at the University of East Anglia (UEA) and Oxford BioDynamics (OBD) have created a high-accuracy blood test to diagnose myalgic encephalomyelitis, also known as chronic fatigue syndrome (ME/CFS). This debilitating long-term illness affects millions worldwide, but is poorly understood and has long lacked reliable diagnostic tools.

“ME/CFS is a serious and often disabling illness characterised by extreme fatigue that is not relieved by rest,” explained lead researcher Professor Dmitry Pshezhetskiy, from UEA’s Norwich Medical School. “We know that some patients report being ignored or even told that their illness is ‘all in their head’.

“With no definitive tests, many patients have gone undiagnosed or misdiagnosed for years. We wanted to see if we could develop a blood test to diagnose the condition — and we did!”

The team used EpiSwitch 3D genomics technology from OBD to see how DNA is folded in blood samples from 47 patients with severe ME/CFS and 61 healthy controls, and discovered a unique pattern that appears consistently in people with ME/CFS that is not seen in healthy people. EpiSwitch has already been proven to deliver practical, rapid blood diagnostics accessible at scale, having shown success in identifying disease-specific blood markers in highly complex inflammatory and neurological conditions such as fast ALS (amyotrophic lateral sclerosis), rheumatoid arthritis and certain cancers.

This latest work, described in the Journal of Translational Medicine, looked beyond the linear DNA sequence investigated by a previously published DecodeME study — understood to be the largest genetic investigation of ME/CFS to date. By examining 3D genomic folds, UEA and OBD revealed hundreds of additional changes, including five of the eight sites identified by DecodeME, which can now provide a deeper understanding of the disease.

The analysis was found to demonstrate 92% sensitivity in identifying ME/CFS, which indicates how well the test identifies those who have the disease (a show of true positives), and 98% specificity, which indicates how well it identifies those who do not have the disease. The researchers also found signs of immune system and inflammation pathways involved in the disease, which may help guide future treatments and identify patients more likely to respond to specific therapies.

“Chronic fatigue syndrome is not a genetic disease you’re born with; that’s why using EpiSwitch epigenetic markers — which can change during a person’s life, unlike fixed genetic code — was key to reaching this high level of accuracy,” said OBD Chief Scientific Officer Alexandre Akoulitchev.

“With this breakthrough, we are proud to enable a first-in-class test that can address an unmet need for a quick and reliable diagnostic for a complex, challenging-to-identify illness.”

“This is a significant step forward,” Pshezhetskiy said. “For the first time, we have a simple blood test that can reliably identify ME/CFS — potentially transforming how we diagnose and manage this complex disease.

“Additionally, understanding the biological pathways involved in ME/CFS opens the door to developing targeted treatments and identifying which patients might benefit most from specific therapies.”

The breakthrough could therefore lead to earlier support and more effective management for those living with ME/CFS — and it is hoped that it could pave the way for a similar blood test to diagnose long COVID.

“Post-COVID syndrome, commonly referred to as long COVID, is one example of ME/CFS, where a similar cluster of symptoms is triggered by the COVID-19 virus, rather than by other known causes such as glandular fever,” Pshezhetskiy said. “We therefore hope that our research will also help pave the way for a similar test to accurately diagnose long COVID.”

Image credit: iStock.com/Irina Romanova