Researchers say they have developed the world’s first reliable blood test to diagnose myalgic encephalomyelitis, also known as chronic fatigue syndrome (ME/CFS).
Currently, there is no definitive test for the illness, which often leaves patients undiagnosed or misdiagnosed for years. Diagnosis is typically based on symptoms such as severe, unrelenting fatigue that does not improve with rest.
The new test, developed by scientists at the University of East Anglia (UEA) and Oxford Biodynamics (OBD), could mark a major breakthrough. However, independent experts have urged caution, saying larger, more rigorous studies are needed to confirm the results before the test can be used in clinics.
“ME/CFS is a serious and often disabling condition,” said Prof Dmitry Pshezhetskiy from UEA’s Norwich Medical School. “Many patients are ignored or told their illness is psychological. Our discovery offers the potential for a simple, accurate test that could transform diagnosis and treatment.”
The team studied how DNA is folded — a process known as epigenetic regulation — in blood samples from 47 patients with severe ME/CFS and 61 healthy individuals. They found a consistent pattern unique to those with ME/CFS, enabling the creation of a diagnostic test.
Published in the Journal of Translational Medicine, the study reports a sensitivity of 92% and a specificity of 98%, meaning the test correctly identifies almost all true cases and rules out nearly all false ones.
“This is a significant step forward,” Pshezhetskiy said. “For the first time, we have a test that can reliably detect ME/CFS.”
OBD’s chief scientific officer, Dr Alexandre Akoulitchev, said the key was identifying “epigenetic markers,” which can change over time and reflect environmental and biological stress, unlike fixed genetic code.
Experts welcomed the findings but stressed that further research is essential. Dr Charles Shepherd from the ME Association said: “It’s an important step, but we need to know whether these markers appear early in the illness and that they’re not found in similar conditions like autoimmune diseases.”
Prof Chris Ponting of the University of Edinburgh added that the claims were “premature” and warned that the test, even if proven effective, could be costly — potentially around £1,000 per patient.
Despite the need for more evidence, researchers and patients alike see the test as a potential turning point in how ME/CFS is recognised and diagnosed.