In the world of medicine there are still many biological mysteries yet to be solved. Chronic fatigue syndrome (CFS) is one of those big unsolved mysteries but a team from Columbia University is bringing us closer to understanding this elusive disorder, finding a specific metabolic fingerprint for the condition that could lead to a new diagnostic tool for doctors.

Chronic fatigue syndrome (CFS), also known as myalgic encephalomyelitis (ME), is a controversial condition identified by a variety of symptoms, from severe fatigue and muscle pain, to allergies, depression and impaired memory. Other than targeting specific symptoms, there is no effective treatment for CFS, and despite a growing body of strong physiological evidence, some in the medical community still persist in labeling it a psychological condition.

Last year, a team of researchers from the Center for Infection and Immunity at Columbia University's Mailman School of Public Health revealed sufferers of CFS displayed microbiome profiles that were unique to the disorder. Compared to a healthy control group, the researchers found that CFS patients could be identified by having abnormally high levels of certain bacteria in the gut.

Following on from that research the team moved to studying the particular blood metabolite profile of CFS patients and analyzed plasma samples from 50 CFS sufferers compared to 50 healthy control subjects. Over 500 different metabolic biomarkers were examined and the researchers homed in on several that were significantly altered in relation to the healthy control group.

When a predictive model was generated to diagnose CFS using these blood biomarkers the researchers reached an accuracy rate of over 80 percent. A comprehensive model was then generated combining the metabolic markers and the previously studied microbiome markers. This model could accurately predict the presence of CFS with 84 percent certainty.

"This is a strong predictive model that suggests we're getting close to the point where we'll have lab tests that will allow us to say with a high level of certainty who has this disorder," says Dorottya Nagy-Szakal, first author on the new study.

Other than offering a pathway towards a much-needed diagnostic tool for the disorder, it's hoped this research will lead to a better understanding of what causes this devastating condition. One outcome the researchers suggest is that animal models be developed that simulate these same metabolic and microbiome footprints. If those animals subsequently display CFS symptoms and behaviours it means that those specific parameters are playing a causal role in the disorder.

"We're getting close to the point where we can develop animal models that will allow us to test various hypotheses, as well as potential therapies, says W. Ian Lipkin, director of the Center for Infection and Immunity. "For instance, some patients might benefit from probiotics to retune their gastrointestinal microflora or drugs that activate certain neurotransmitter systems."

It's estimated that up to two million people suffer from CFS in the United States alone. While the majority of doctors have come to accept it as a valid clinical physiological condition, many are still reticent to diagnose it due to the lack of clearly defined biological markers. It is hoped that this research will help in the diagnosis, and aid development of treatments, for the millions of sufferers of this misunderstood condition.

The study was published in the journal Scientific Reports.