A systematic review and meta-analysis of urinary biomarkers in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS).
Taccori, Asher, Maksoud, Rebekah, Eaton-Fitch, Natalie et al. · Journal of translational medicine · 2023 · DOI
Quick Summary
Researchers looked at 21 studies examining urine samples from ME/CFS patients to find markers that could help diagnose the condition. They focused especially on a substance called cortisol (a stress hormone) in urine. While they found some differences in urine samples between people with ME/CFS and healthy people, the results were too inconsistent to identify a reliable single marker for diagnosis.
Why It Matters
ME/CFS currently lacks a definitive diagnostic test, making non-invasive urine-based biomarkers potentially valuable for diagnosis and understanding disease mechanisms. This systematic review synthesizes existing evidence to identify gaps in research and guide future studies toward more reliable diagnostic approaches. Understanding urinary markers could help clinicians identify ME/CFS earlier and advance understanding of the condition's multisystem effects.
Observed Findings
Urinary free cortisol was investigated most frequently (38.1% of studies) and showed consistent differences between ME/CFS patients and controls
Carnitine levels in urine were examined in 28.6% of studies
Metabolomic (full chemical profile) changes were reported in 42.86% of studies
Substantial heterogeneity existed across studies in methodology, making direct comparisons difficult
Minimal overlap in measured outcomes prevented unified conclusions about specific biomarkers
Inferred Conclusions
Limited evidence currently supports any single urinary biomarker as a consistent and specific diagnostic marker for ME/CFS
Urinary free cortisol shows promise but requires standardized collection and analysis methods before clinical application
Future research must employ more rigorous study designs with standardized case definitions to identify genuine pathophysiological differences
Multisystem involvement in ME/CFS may require examining multiple urinary markers rather than relying on a single biomarker
Remaining Questions
Which urinary biomarkers, when measured with standardized protocols, would show sufficient specificity and sensitivity for clinical diagnosis?
What This Study Does Not Prove
This review does not establish that any single urinary biomarker can reliably diagnose ME/CFS. The substantial heterogeneity across studies means findings cannot yet be translated into clinical practice. The review also cannot determine whether urinary changes are causes or consequences of ME/CFS pathology.