Preliminary determination of the association between symptom expression and urinary metabolites in subjects with chronic fatigue syndrome.
McGregor, N R, Dunstan, R H, Zerbes, M et al.·Biochemical and molecular medicine·1996
Researchers found that ME/CFS patients have a distinctive substance in their urine called CFSUM1 that is rarely found in healthy people. This study examined whether certain chemicals in urine could be linked to the different symptoms ME/CFS patients experience, such as fatigue, cognitive problems, muscle pain, and digestive issues. They discovered that two specific urine metabolites—CFSUM1 and beta-alanine—were strongly associated with symptom severity, suggesting these could eventually be used as biological markers for diagnosing ME/CFS.