Researchers at Stanford School of Medicine have identified a biomarker they believe could help identify chronic fatigue syndrome through a blood test, offering relief to the millions of people globally who suffer from the debilitating disease.

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a poorly understood disease that lacks thorough diagnostic tools and treatments. Diagnosis is often based on symptoms that include exhaustion, sensitivity to light, and unexplained pain, and only comes after another possible disease has been eliminated.

“Too often, this disease is categorized as imaginary,” said study author Ron Davis in a statement. Generally, those with ME/CFS undergo a series of tests that check liver, kidney, and heart function as well as immune cell counts, but Davis says these measures don’t do enough. “All of these different tests would normally guide a doctor toward one illness or another, but for chronic fatigue syndrome patients, the results all come back normal."

Though the study is still in its pilot phase, researchers say their method can correctly identify whether a person has the disease based on how their immune cells respond to stress.

To do so, they took blood samples from 40 people (20 with ME/CFS and 20 without) and added salt to stress it. They then used a technology called nanoelectronics assay, which measures changes in minuscule amounts of energy and serves as an indicator for the health of immune cells and blood plasma. Their diagnostic tool has thousands of electrodes that create an electrical current through the blood – how it changes in response to this current is directly correlated with the health of it. The blood of those with ME/CFS exhibited the biggest changes on a cellular level, indicating that their cells and plasma don’t process stress properly and instead flail under it. Blood taken from healthy participants returned to normal after seeing only a minor spike.

“We don’t know exactly why the cells and plasma are acting this way, or even what they’re doing,” Davis said. “But there is scientific evidence that this disease is not a fabrication of a patient’s mind. We clearly see a difference in the way healthy and chronic fatigue syndrome immune cells process stress.” 

Davis notes that the work could help identify potential drugs to treat disease. Already, his team has found a candidate drug that restores healthy function to immune cells and plasma. Though it is not being currently used to treat people, he is hopeful a clinical trial may be possible in the future.  

The study was published in the Proceedings of the National Academy of Sciences.