After decades of frustration and uncertainty, a team of scientists in the UK has unveiled a groundbreaking blood test that promises to transform the diagnosis of myalgic encephalomyelitis, also known as chronic fatigue syndrome (ME/CFS). The test, developed by researchers at the University of East Anglia and Oxford BioDynamics, marks a significant leap forward for millions of patients worldwide who have long struggled to obtain a definitive diagnosis for this debilitating condition.
The new diagnostic tool, detailed in the Journal of Translational Medicine on October 8, 2025, is the first of its kind to offer high accuracy in identifying ME/CFS. According to the study, the test achieved a remarkable 96% overall accuracy, with 92% sensitivity and 98% specificity, when validated on blood samples from severely affected patients and healthy volunteers. For those living with ME/CFS—an illness that affects more than 400,000 people in the UK and millions globally—this development could finally bring clarity after years of medical uncertainty.
Historically, diagnosing ME/CFS has been a process fraught with doubt and disbelief. Patients often endure years of symptoms such as extreme fatigue, brain fog, unrefreshing sleep, and a dramatic worsening of symptoms after even minor exertion. Because there has been no objective laboratory test, diagnosis has relied on clinical judgment and the exclusion of other conditions—leaving many patients feeling dismissed or misunderstood by the medical community. As the researchers wrote in their study, “ME/CFS lacks definitive diagnostic biomarkers, complicating diagnosis and management.”
The breakthrough blood test, dubbed EpiSwitch CFS, takes a novel approach. Instead of searching for changes in the genetic code itself, the test analyzes how DNA is folded and organized inside blood cells—a field known as epigenetics. This folding determines which genes are turned on or off, and in people with ME/CFS, it creates a unique signature that can be detected in a simple blood draw. “We wanted to see if we could develop a blood test to diagnose the condition – and we did,” stated Professor Dmitry Pshezhetskiy, the study’s lead researcher at the University of East Anglia, as reported by BBC.
To develop the test, the team collected blood samples from 47 severely ill ME/CFS patients and 61 healthy controls. Using advanced laboratory platforms and machine learning, they scanned each sample for DNA folding patterns across one million different sites, ultimately identifying 200 specific markers that could reliably distinguish patients from healthy individuals. The technology behind the test is already in use for cancer diagnostics, making it more accessible than previous attempts that required specialized equipment.
What’s especially intriguing is that these markers were scattered across multiple chromosomes, suggesting that ME/CFS disrupts the body’s regulatory systems in a widespread manner. Further analysis revealed that many of these markers are linked to immune signaling pathways, particularly those involving interleukin-2—a molecule that helps coordinate the immune system’s response to infection. This finding dovetails with longstanding patient reports that ME/CFS often develops after a viral illness.
“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,” explained Alexandre Akoulitchev, chief scientific officer at Oxford BioDynamics, in a company press release. The study, which was funded and co-authored by Oxford BioDynamics, also received approval from the UK National Ethics Service and followed established ethical guidelines.
One of the most compelling aspects of the research is the potential to identify different subtypes of ME/CFS. When the team examined immune marker patterns, they found that patients clustered into two distinct groups—about 60% in one pattern and 40% in another. This could help explain why some patients respond to certain treatments while others do not, and may pave the way for more personalized approaches to care.
For patients, the implications are profound. A reliable blood test could not only validate their experience but also streamline access to support, disability claims, and more targeted interventions. “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,” said Professor Pshezhetskiy. For many, simply having a concrete answer—something to point to on a lab report—would be a huge relief after years of being told their symptoms were “all in their head.”
However, experts caution that the road to widespread clinical use is not without hurdles. The initial studies focused on patients with severe, housebound illness, and the validation samples came from the same blood bank collections. Independent experts, such as Dr. Charles Shepherd, medical adviser to the ME Association, have emphasized the need for further validation in more diverse patient groups, including those with mild or moderate symptoms and those in the early stages of the disease. The test also needs to be compared against samples from patients with other illnesses that can mimic ME/CFS, such as multiple sclerosis or rheumatoid arthritis, to ensure its specificity.
Moreover, the research has not established whether the immune changes detected by the test are a cause or a consequence of ME/CFS. As the Journal of Translational Medicine study notes, “The study shows association between markers and disease but can’t prove the immune changes cause ME/CFS.” Larger, multi-center studies and independent replication will be necessary before the test can become a routine part of clinical practice.
Oxford BioDynamics, for its part, is actively seeking partners to co-develop or license the test, with hopes of bringing it to market in the near future. The company also sees potential for adapting the technology to diagnose post-COVID syndrome (long COVID), a condition with overlapping symptoms and growing global impact.
While the new blood test remains experimental for now, its promise is undeniable. For a community that has spent years in the medical shadows, the prospect of a definitive, accessible diagnostic tool is a beacon of hope. As the science progresses, patients and clinicians alike are watching closely, eager for a future where ME/CFS is not just recognized, but understood—and, eventually, more effectively treated.
