Chronic Fatigue Syndrome (CFS), also known as Myalgic Encephalomyelitis (MS), is a debilitating and misunderstood disease, defined more precisely because it is not what it is.
Without a known cause, few unique symptoms and little more for doctors to pass, it is difficult to get a reliable and consistent diagnosis.
A simple blood test can change all that, and Stanford researchers think they may have discovered the right test. In a 40-person pilot study, the team was able to identify each of the 20 participants with CFS based solely on how their immune cells respond to stress.
All that was needed was a small amount of blood and an ultra-sensitive tool known as a "nanoelectronic assay", which can monitor cellular events in real time from a very small sample volume.
Using thousands of electrodes, this machine measures changes in the electrical activity of blood samples, an indicator of how well cells and plasma are working.
To mimic the stress of post-effort fatigue – a classic symptom of CFS – the authors bathed all their blood samples in a salty environment. Under these conditions, the trial findings clearly show a peak in the blood test of patients with CFS, while the results of healthy controls remained relatively stable.
"We do not know exactly why cells and plasma are acting that way, or even what they are doing," says co-author Ron Davis, a biochemist at Stanford University.
"But there is scientific evidence that this disease is not an invention of a patient's mind. We clearly see a difference in how immune cells, the healthy and chronic fatigue syndrome, process stress."
Excited by their results, the authors are already using the biomarker as a filter for potential CFS drugs, one of which shows a particular promise when tested using the assay.
"This is a low cost, rapid, miniaturized, minimally invasive and highly sensitive assay," the authors conclude.
"Given the significance of this assay and its reliability, we imagine it has the potential to be widely employed in other research labs and clinics in the near future as an aid to physicians as well as to our colleagues in the ME / CFS research community . "
The announcement has many understandably excited – after all, it is believed that this disease affects up to 24 million people worldwide. But for now, we need to temper our excitement.
The reality is that it is too early to say whether these electrical disturbances are a true biomarker of CFS. The sample size of this study was only 20 patients, and the findings still need to be replicated in a larger cohort or by an independent team.
Moreover, the method has not been tested in other diseases that behave similarly to CFS.
While some experts outside the study were enthusiastic about the results, others expressed frustration with part of the coverage, where the results were exaggerated.
Simon Wessely, a psychiatrist at King's College London who has worked with patients with CFS for many years, told NBC that there are still many questions that the Stanford study left unsolved.
"The (first) question is: can any biomarker distinguish patients with CFS from those with other fatiguing diseases? And, second, measure the cause and not the consequence of the disease?" he said in an e-mail comment. "This study provides no evidence that it has finally been achieved."
Meanwhile, Dr. Andrew Lloyd of the University of New South Wales told New Atlas that he thought it was too early to call it SFC's target biological marker.
To summarize: it is okay to hope for these results; just do not get too excited about the prospect of a definitive blood test coming soon.
"It's an important milestone," said Robert Naviaux, a UC San Diego geneticist who is familiar with Stanford's work but was not involved. The San Francisco Chronicle.
"If this continues in greater numbers, this can be a transformational breakthrough."
This study was published in PNAS.