Summary
| Direction in ME/CFS | ↕ Inconsistent — reported as both higher and lower across studies, with no consistent direction |
|---|---|
| Category | Inflammatory |
| Also described as | Chemokine |
| Compared against | HC (healthy controls) |
| Associated symptoms | Neutrophil recruitment |
| Test type | Blood test (serum / plasma / whole blood) |
| LOINC code | 26998-9 |
| Source | Corbitt et al. 2019 — doi:10.1016/j.psyneuen.2019.05.008 |
| Condition atlas | ME/CFS Biomarker Atlas |
Other conditions where Interleukin-8 (IL-8 / CXCL8) is reported
- Interleukin-8 (IL-8 / CXCL8) in Gulf War Illness — ↑ elevated vs HGV
- Interleukin-8 (IL-8) in Long COVID — ↑ elevated vs HC
- IL-8 in PACVS — ↑ elevated vs HC
See the cross-condition hub: Interleukin-8 (IL-8 / CXCL8) across conditions.
Trials, interventions and tests
In clinical-trial registrations this marker maps to the outcome term Assessment of Changes in Exosome/Cytokine/Chemokine Testing (4 registered trials use a matching outcome measure).
Clinical trials using Interleukin-8 (IL-8 / CXCL8) as an outcome
- NCT05833217: Obesity, Insulin Resistance, and PASC: Persistent SARS-CoV-2 (Recruiting)
Outcome measure: Rate of Inflammatory Gene Expression in Adipose Tissue - NCT06535165: Effect of Red Beetroot Juice Intake in Adults With Long COVID-19 (Completed)
Outcome measure: Changes in the concentration of circulating inflammatory mediators - NCT05669261: Treatment of Long COVID Symptoms Utilizing Autologous Stem Cells Following COVID-19 Infection (Unknown)
Outcome measure: Assessment of Changes in Exosome/Cytokine/Chemokine Testing - NCT05874089: VSL#3® vs Placebo in the Treatment of Fatigue and Other Symptoms in Long Covid (DELong#3) (Unknown)
Outcome measure: Analysis of PBMC and Serum Expression of inflammatory mediators at baseline (t0) and after 4 weeks of treatment (t4)
Commercial test availability
Interleukin-8 (IL-8) — specialty laboratory test.
Links are for reference only; availability, specimen requirements and coverage vary by location.
Related Inflammatory markers in ME/CFS
- Interleukin-6 (IL-6) ↕
- Interleukin-10 (IL-10) ↕
- Tumor Necrosis Factor-α (TNF-α) ↕
- C-Reactive Protein (CRP) ↕
- Transforming Growth Factor-β (TGF-β) ↑
- Leptin ↑
- Interleukin-1 (IL-1α/β) ↑
- Resistin ↕
Full list: ME/CFS Biomarker Atlas.
Frequently asked questions
Is Interleukin-8 (IL-8 / CXCL8) high or low in ME/CFS?
Mixed. Some studies report higher and others lower Interleukin-8 (IL-8 / CXCL8) in ME/CFS compared with healthy controls, so no single direction is established. Source: Corbitt et al. 2019.
What symptoms is Interleukin-8 (IL-8 / CXCL8) associated with in ME/CFS?
The cited literature associates this marker with Neutrophil recruitment. These are population-level associations and do not mean the marker causes the symptoms.
Which test measures Interleukin-8 (IL-8 / CXCL8)?
It is measured as a blood test (serum / plasma / whole blood). The standard laboratory code is LOINC 26998-9. Commercial laboratories such as Quest Diagnostics, LabCorp list an orderable assay.
Is one abnormal Interleukin-8 (IL-8 / CXCL8) result diagnostic of ME/CFS?
No. No single biomarker is diagnostic of ME/CFS. Interleukin-8 (IL-8 / CXCL8) findings come from group comparisons, overlap considerably between patients and controls, and vary with study design, timing and comparison group. A result should be interpreted by a clinician alongside symptoms, history and other tests.
Is Interleukin-8 (IL-8 / CXCL8) specific to ME/CFS?
No. The same marker is also reported in Gulf War Illness, Long COVID, PACVS in this atlas, so it reflects shared biology (for example inflammation or vascular stress) rather than a condition-specific signature.
Cite this page
Subscribe on Substack
Last reviewed: 2026-06-29 · Page generated from me-cfs.json · Browse: ME/CFS atlas · Biomarker Index · All marker pages
Disclaimer: This page is an educational synthesis of published, peer-reviewed research and is not medical advice. Biomarker findings vary across studies with case definitions, comparison groups, timing and assay methods. Direction of change reflects the predominant finding in the cited source and does not establish a diagnostic threshold. Discuss any test result with a qualified clinician.