Summary
| Direction in Gulf War Illness | ↕ Inconsistent — reported as both higher and lower across studies, with no consistent direction |
|---|---|
| Category | Autoimmune |
| Also described as | Autoimmune marker |
| Compared against | HGV (healthy Gulf War veteran controls) |
| Associated symptoms | Joint pain subset |
| Test type | Blood test (serum / plasma / whole blood) |
| Source | Gean et al. 2021 — doi:10.1016/j.lfs.2021.119456 |
| Condition atlas | Gulf War Illness Biomarker Atlas |
Other conditions where Rheumatoid factor (RF) is reported
- Rheumatoid Factor in Rheumatoid Arthritis — ↑ elevated vs RA (positive in 80-85%) vs healthy (rare)
See the cross-condition hub: Rheumatoid factor (RF) across conditions.
Trials, interventions and tests
In clinical-trial registrations this marker maps to the outcome term Rate and evolution of autoimmune markers at month 3 and month 6 (1 registered trials use a matching outcome measure).
Clinical trials using Rheumatoid factor (RF) as an outcome
- NCT05543590: Effect of Plasmapheresis on Clinical Improvement and Biological Parameters of Patients With Long-haul COVID (Withdrawn)
Outcome measure: Rate and evolution of autoimmune markers at month 3 and month 6
Related Autoimmune markers in Gulf War Illness
- Anti-nuclear antibodies (ANA) ↕
- Anti-acetylcholine receptor antibodies ↑
- β2-adrenergic receptor autoantibodies ↑
- Muscarinic receptor autoantibodies ↑
Full list: Gulf War Illness Biomarker Atlas.
Frequently asked questions
Is Rheumatoid factor (RF) high or low in Gulf War Illness?
Mixed. Some studies report higher and others lower Rheumatoid factor (RF) in Gulf War Illness compared with healthy Gulf War veteran controls, so no single direction is established. Source: Gean et al. 2021.
What symptoms is Rheumatoid factor (RF) associated with in Gulf War Illness?
The cited literature associates this marker with Joint pain subset. These are population-level associations and do not mean the marker causes the symptoms.
Which test measures Rheumatoid factor (RF)?
It is measured as a blood test (serum / plasma / whole blood). Many of the cited studies used research-grade assays, so clinical availability may vary.
Is one abnormal Rheumatoid factor (RF) result diagnostic of Gulf War Illness?
No. No single biomarker is diagnostic of Gulf War Illness. Rheumatoid factor (RF) 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 Rheumatoid factor (RF) specific to Gulf War Illness?
No. The same marker is also reported in Rheumatoid Arthritis in this atlas, so it reflects shared biology (for example inflammation or vascular stress) rather than a condition-specific signature.
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Last reviewed: 2026-06-29 · Page generated from gulf-war-illness.json · Browse: Gulf War Illness 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.