Chronic fatigue blood test is 92% sensitive, 98% specific: will it finally help 400,000 Britons?

After years of uncertainty and doubt, people with crushing exhaustion may soon see objective answers emerge from the lab.

Researchers in Norwich and Oxford say a new blood test can spot a biological signature of myalgic encephalomyelitis/chronic fatigue syndrome, offering a path away from symptom-only diagnosis and towards faster, fairer care.

What has changed

A team from the University of East Anglia and Oxford Biodynamics has reported a laboratory test that identifies distinctive DNA folding patterns in blood from people with ME/CFS. The assay, built on Oxford Biodynamics’ EpiSwitch 3D Genomics platform, reportedly reached 92% sensitivity and 98% specificity in distinguishing patients from controls. These figures, if reproduced independently at scale, would put an objective diagnostic within reach for a condition that affects an estimated 400,000 people in the UK.

The assay reads 3D DNA folding patterns, returning 92% sensitivity and 98% specificity in initial testing.

Today, clinicians diagnose ME/CFS by clinical history, exclusion of other causes, and persistence of hallmark symptoms such as post-exertional malaise, unrefreshing sleep, cognitive slowing, and autonomic complaints. That process can take months or years, with people often mislabelled as anxious, depressed, or deconditioned. An objective lab result could shorten the ordeal and legitimise access to support, pacing strategies, and employer adjustments.

How the test works

EpiSwitch technology measures the three-dimensional architecture of DNA inside the cell. While the genetic code stays the same, the way DNA loops, folds, and interacts with regulatory elements changes with disease and inflammation. The new assay looks for a pattern of these “3D genomic” markers that appears consistently in ME/CFS.

In practice, a standard blood sample is processed to capture these structural signatures. A trained algorithm then classifies the sample as consistent with ME/CFS or not. The readout does not identify severity or predict prognosis; it speaks to the presence of a molecular fingerprint seen in the condition.

Why diagnosis matters

ME/CFS carries a heavy burden. People struggle with disabling fatigue, post-exertional symptom flares, orthostatic intolerance, pain, light and sound sensitivity, and brain fog. Many leave work or education. Without a definitive test, patients can face disbelief, delayed benefits, and limited care pathways. A lab-backed result could change how GPs triage, how employers accommodate, and how insurers assess claims.

For many patients who currently wait years for an answer, a validated assay could cut the diagnostic journey to a single blood draw.

Early confirmation also helps researchers build cleaner study cohorts, accelerating drug development and biomarker discovery. With rates of post-viral fatigue syndromes rising since the pandemic, the need for reliable tools has intensified.

What researchers still need to prove

Enthusiasm is tempered by calls for independent replication. Specialists want to see performance across diverse groups, including different ages, ethnicities, and disease severities, and in people with overlapping conditions. They also want head-to-head comparisons with illnesses that present similarly.

Key questions for the next studies

• Does the signature hold in primary care settings, not just specialist clinics?
• Can the assay distinguish ME/CFS from long Covid, fibromyalgia, POTS, depression, anaemia, and hypothyroidism?
• How stable are the markers during relapse and remission, and after infections or vaccinations?
• What is the test’s performance in adolescents and older adults?
• How does medication use, including SSRIs, antihistamines, or beta-blockers, affect results?
• What are turnaround times and per-test costs in routine NHS laboratories?

Implications for clinics and patients

How GP appointments could change

If validated and approved, GPs could add the assay to an investigative bundle once red flags are excluded. The result would not replace clinical judgement, but it could guide earlier pacing advice, symptom-targeted care, and faster referral to specialist services. For employers, a biomarker may make workplace adjustments easier to justify.

Commissioners will watch cost-effectiveness closely. A test with 98% specificity helps avoid labelling the well as ill, reducing downstream costs. Sensitivity at 92% leaves some missed cases, so clinicians will still need to listen and consider repeat testing if suspicion remains high.

The science in plain language

Think of the genome as a long thread. Cells fold and loop that thread so distant pieces can touch and switch genes on or off. Disease changes the folding pattern. By measuring those folds, the assay detects a disease “posture” of the genome, without altering the underlying DNA letters. It is like reading body language rather than the birth certificate.

What you should know right now

• The test is not yet routine in the NHS. Wider validation and regulatory review would come before rollout.
• A positive result would support a diagnosis when combined with history and examination.
• A negative result does not erase symptoms. Clinicians may retest or reconsider if signs still point to ME/CFS.
• People with persistent post-exertional malaise should keep activity diaries and bring them to appointments.
• Participation in ethically approved studies helps speed validation and access.

Numbers in context: what accuracy means for you

Accuracy numbers feel reassuring, but context matters. In a general population where ME/CFS is uncommon, even a small false-positive rate can generate many incorrect positives. Imagine 100,000 adults tested outside specialist clinics. If 0.6% actually have ME/CFS (about 600 people), a test with 92% sensitivity would flag roughly 552 true positives, while 98% specificity would still produce around 1,988 false positives among the 99,400 without the condition. Many positive results would then need clinical review to sort signal from noise. In a clinic where suspected prevalence is higher, the proportion of true positives rises sharply. This is why doctors will pair the assay with a careful history and examination.

Where this could lead next

Biomarkers can do more than label a disease. Once validated, they can stratify patients into subgroups, guide trials, and track treatment response. A 3D genomic signature might help separate post-viral immune phenotypes from autonomic-dominant cases, opening the door to targeted therapies. Researchers will also test whether similar patterns appear in long Covid, which shares post-exertional worsening and autonomic features with ME/CFS. If overlaps exist, the assay could help map the biology that these conditions share—and where they differ.

People considering private testing should weigh the risks. Unregulated offerings can be expensive and may not stand up to clinical scrutiny. Waiting for peer-reviewed validation and clear clinical pathways reduces confusion and protects budgets. Patients and carers can use this window to prepare: organise medical histories, document activity limits, and speak with workplaces about flexible adjustments that reduce post-exertional crashes. Should the test enter practice, being ready could turn a lab result into practical support within days, not months.