Assessing cellular energy dysfunction in CFS/ME using a commercially available laboratory test.
Tomas, Cara, Lodge, Tiffany A, Potter, Michelle et al. · Scientific reports · 2019 · DOI
Quick Summary
This study tested a blood test called the Mitochondrial Energy Score (MES) that is marketed to diagnose ME/CFS by measuring how well cells produce energy. Researchers repeated the test in both ME/CFS patients and healthy people and found no difference between the two groups. They also discovered that waiting even 24 hours before processing blood samples changed the test results significantly, suggesting the test is not reliable enough to use for diagnosis.
Why It Matters
Many ME/CFS patients have explored the MES test as a potential diagnostic tool, but this study provides important evidence that it should not be relied upon for diagnosis. Understanding which biomarker tests are genuinely reliable versus those with methodological limitations is crucial for patients making healthcare decisions and for researchers pursuing valid diagnostic approaches.
Observed Findings
No significant differences were found between CFS/ME patients and healthy controls in any MES components using the standard protocol (p ≥ 0.059)
Delaying blood sample processing by 24 hours significantly altered multiple parameters in both neutrophils and PBMCs
The 24-hour delay effects were observed in healthy control samples, indicating pre-analytical variables affected test results
The Myhill group's quoted 72-hour processing window was not validated for maintaining test reliability
Differences reported by the Myhill group may be attributable to variations in sample processing time between comparison groups
Inferred Conclusions
The MES test does not have sufficient reliability and reproducibility to be offered as a diagnostic test for ME/CFS
Previously reported differences between patient and control groups by the Myhill group likely resulted from uncontrolled pre-analytical variables rather than true biomarker differences
Sample processing time is a critical pre-analytical variable that requires strict standardization for blood-based biomarker testing
The test requires substantial methodological validation and standardization before clinical application can be considered
Remaining Questions
What This Study Does Not Prove
This study does not prove that mitochondrial dysfunction does not occur in ME/CFS—only that this particular test cannot reliably measure it. It also does not establish whether the Myhill group's original findings were fraudulent or merely methodologically flawed due to uncontrolled sample processing variables.