Yamamoto, Yukichika, Otsuka, Yuki, Tokumasu, Kazuki et al. · Journal of clinical medicine · 2023 · DOI
This study looked at 234 people with long COVID to understand why some developed ME/CFS (a severe fatigue condition) while others didn't. Researchers found that people who developed ME/CFS had significantly higher levels of ferritin, a protein that stores iron, in their blood compared to those with long COVID fatigue alone or no fatigue. The finding was especially strong in women, suggesting that a simple blood test measuring ferritin might help predict who is at risk of developing ME/CFS after COVID-19.
ME/CFS remains diagnostically challenging, with no established biomarkers; identifying serum ferritin as a potential predictor could facilitate earlier recognition and stratification of high-risk long COVID patients. This finding opens new avenues for understanding the biological mechanisms linking infection-triggered inflammation to ME/CFS pathophysiology. For patients, a simple blood test could help predict disease trajectory and enable earlier intervention.
This study demonstrates correlation between elevated ferritin and ME/CFS development but does not establish causation—ferritin elevation may be a consequence rather than a driver of ME/CFS pathology. The observational design prevents determination of whether ferritin itself plays a mechanistic role or merely serves as a marker of underlying inflammatory processes. Results require validation in prospective cohorts and are not generalizable beyond long COVID populations.
About the PEM badge: “PEM required” means post-exertional malaise was an explicit required diagnostic criterion for participant inclusion in this study — not that PEM was studied, observed, or discussed. Studies using criteria that do not require PEM (e.g. Fukuda, Oxford) are tagged “PEM not required”. How the atlas works →
The first block is for the primary paper and is the citation you should use in research work. The atlas-snapshot line only applies if you are specifically referring to this atlas’s reading of the paper on the date shown.
Primary citation
Yamamoto, Yukichika, Otsuka, Yuki, Tokumasu, Kazuki, Sunada, Naruhiko, Nakano, Yasuhiro, Honda, Hiroyuki, et al. (2023). Utility of Serum Ferritin for Predicting Myalgic Encephalomyelitis/Chronic Fatigue Syndrome in Patients with Long COVID.. Journal of clinical medicine. https://doi.org/10.3390/jcm12144737
BibTeX
@article{mecfsatlas-yamamoto-2023-utility-serum,
author = {Yamamoto, Yukichika and Otsuka, Yuki and Tokumasu, Kazuki and Sunada, Naruhiko and Nakano, Yasuhiro and Honda, Hiroyuki and Sakurada, Yasue and Hasegawa, Toru and Hagiya, Hideharu and Otsuka, Fumio},
title = {Utility of Serum Ferritin for Predicting Myalgic Encephalomyelitis/Chronic Fatigue Syndrome in Patients with Long COVID.},
journal = {Journal of clinical medicine},
year = {2023},
doi = {10.3390/jcm12144737},
note = {PubMed: 37510852},
url = {https://www.mecfsatlas.com/evidence/yamamoto-2023-utility-serum},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-30. https://www.mecfsatlas.com/evidence/yamamoto-2023-utility-serum
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