Baklund, Ingrid H, Dammen, Toril, Moum, Torbjørn Åge et al. · Journal of clinical medicine · 2021 · DOI
Researchers compared blood test results from 149 ME/CFS patients with 264 healthy people to look for differences. They found that ME/CFS patients had higher levels of inflammation markers and certain blood cells, along with lower potassium and muscle enzyme levels. These differences suggest that ME/CFS may involve both inflammation and possible muscle or metabolic problems.
This study provides objective laboratory evidence that ME/CFS patients show distinct blood abnormalities compared to healthy individuals, potentially supporting biological validation of the condition. Identifying these patterns may eventually help clinicians recognize ME/CFS through routine blood work and guide future research into disease mechanisms.
This study does not prove that these blood test changes cause ME/CFS symptoms or that they are specific to ME/CFS alone. The cross-sectional design cannot establish whether these abnormalities are present before symptom onset or develop as a consequence of illness. Additionally, while differences exist statistically, their clinical significance and diagnostic utility in individual patients remain unclear.
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
Baklund, Ingrid H, Dammen, Toril, Moum, Torbjørn Åge, Kristiansen, Wenche, Duarte, Daysi Sosa, Castro-Marrero, Jesus, et al. (2021). Evaluating Routine Blood Tests According to Clinical Symptoms and Diagnostic Criteria in Individuals with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome.. Journal of clinical medicine. https://doi.org/10.3390/jcm10143105
BibTeX
@article{mecfsatlas-baklund-2021-evaluating-routine,
author = {Baklund, Ingrid H and Dammen, Toril and Moum, Torbjørn Åge and Kristiansen, Wenche and Duarte, Daysi Sosa and Castro-Marrero, Jesus and Helland, Ingrid Bergliot and Strand, Elin Bolle},
title = {Evaluating Routine Blood Tests According to Clinical Symptoms and Diagnostic Criteria in Individuals with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome.},
journal = {Journal of clinical medicine},
year = {2021},
doi = {10.3390/jcm10143105},
note = {PubMed: 34300271},
url = {https://www.mecfsatlas.com/evidence/baklund-2021-evaluating-routine},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-26. https://www.mecfsatlas.com/evidence/baklund-2021-evaluating-routine
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