Saliva Fatigue Biomarker Index As a Marker for Severe Myalgic Encephalomyelitis/Chronic Fatigue Syndrome in a Community Based Sample.

Objective: The prevalence of pediatric Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) has been estimated from an ethnically and sociodemographically diverse community-based random sample of 10,119 youth aged 5-17. A team of physicians made a final diagnosis of ME/CFS if the participants met criteria for up to three selected case definitions following medical and psychiatric evaluations. We assessed whether a salivary biomarker of fatigue could identify youth with ME/CFS.

Study Design: We examined the ratio of the concentrations of 2 peptide fragments in saliva, referred to as the Fatigue Biomarker Index (FBI), in participants from our study diagnosed with ME/CFS (n=59) and matched controls (n=39).

Results: Significant overall differences were found in the FBI between those participants with severe ME/CFS and those with ME/CFS and the controls.

Conclusions: If confirmed in other populations, the FBI could serve as an objective test to aid in the diagnosis of severe ME/CFS.