Scientists say they have developed the world’s first blood test to diagnose myalgic encephalomyelitis, also known as chronic fatigue syndrome (ME/CFS).
There is no currently no test for the condition and patients tend to be diagnosed based on symptoms, which means many can go undiagnosed for years.
However, some experts not involved with the research urged caution and said the test would need to be fully validated in better designed and independent studies before it could be considered for use in clinical practice.
The lead researcher, Prof Dmitry Pshezhetskiy, from the University of East Anglia (UEA) Norwich Medical School, said: “ME/CFS is a serious and often disabling illness characterised by extreme fatigue that is not relieved by rest. 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. Our discovery offers the potential for a simple, accurate blood test to help confirm a diagnosis, which could lead to earlier support and more effective management.”
Scientists at UEA and Oxford Biodynamics (OBD) looked at how DNA was folded in patients diagnosed with the condition, which could provide tell-tale signs of ME/CFS.
They examined blood samples from 47 patients with severe ME/CFS and 61 healthy adults. The team discovered a unique pattern that appears consistently in people with ME/CFS that is not seen in healthy people, enabling them to develop the test.
Writing in the Journal of Translational Medicine, they said the test had a sensitivity – or the likelihood of a test being positive if that patient has the condition – of 92%. It had a specificity – the probability the test will rule out negative cases – of 98%.
Pshezhetskiy added: “This is a significant step forward, 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.”
Alexandre Akoulitchev, the chief scientific officer at OBD, which funded and co-authored the research, said: “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.”
However, other experts called for more studies to confirm the finding, and for the test to be assessed among a wider population of patients.
Dr Charles Shepherd, medical adviser for the ME Association, said: “These results, using epigenetic profiling, appear to be an important step forward in the search for a diagnostic blood test.
“However, as the researchers point out, a diagnostic blood test has to be both highly sensitive and specific to that condition. In this case, we therefore need to know whether the abnormality is consistently present in the very early stages of ME/CFS as well as in people with longstanding disease who have mild or moderate ME/CFS.
“We also need to know that, in addition to the abnormality not being present in healthy controls, it is also not present in a range of other chronic inflammatory and autoimmune diseases that cause ME/CFS-like symptoms and form part of the differential diagnosis of ME/CFS.”
Prof Chris Ponting, chair of medical bioinformatics at the University of Edinburgh, said some of the claims made by the research team were “premature”.
He said: “This test needs to be fully validated in better-designed and independent studies before it is considered for clinical application. Even if validated, the test will be expensive, likely (about) £1,000.”
