Researchers in the UK say they have developed the first reliable blood test to diagnose myalgic encephalomyelitis, also known as chronic fatigue syndrome (ME/CFS).
Currently, there is no definitive test for ME/CFS, and diagnoses are based on symptoms, meaning many patients face years of uncertainty or misdiagnosis.
The new study, led by Prof Dmitry Pshezhetskiy from the University of East Anglia (UEA), offers fresh hope to millions living with the condition. “ME/CFS is a serious and often disabling illness,” he said. “Our discovery offers the potential for a simple, accurate blood test to confirm diagnosis and enable earlier support.”
Researchers from UEA and Oxford Biodynamics analysed DNA folding patterns in blood samples from 47 ME/CFS patients and 61 healthy adults. They discovered a distinctive biological signature found only in people with the condition.
The test, published in the Journal of Translational Medicine, demonstrated 92% sensitivity and 98% specificity — meaning it accurately identified most ME/CFS cases while rarely producing false positives.
“This is a significant step forward,” Pshezhetskiy said. “For the first time, we have a reliable test that could transform how we diagnose and manage ME/CFS.”
Dr Alexandre Akoulitchev, chief scientific officer at Oxford Biodynamics, explained that the breakthrough relied on epigenetic markers — chemical changes to DNA that occur during life. “ME/CFS is not a genetic disorder you’re born with,” he said. “Using epigenetic data allowed us to achieve high accuracy.”
However, other experts urged caution. Dr Charles Shepherd of the ME Association called the findings “an important step forward” but said more research was needed to confirm the results.
“We need to know whether this abnormality appears in early-stage patients, and whether it is unique to ME/CFS or found in other chronic conditions,” he said.
Prof Chris Ponting from the University of Edinburgh also warned that the claims may be “premature.” He stressed the need for independent validation before the test is used clinically and noted that, even if approved, it could cost around £1,000 per patient.
Despite these cautions, researchers say the test could mark a turning point in how ME/CFS is diagnosed and understood — offering long-awaited recognition for a condition often dismissed or misunderstood.
