Summary
| Direction in Rheumatoid Arthritis | ↑ Elevated — higher than in the comparison group |
|---|---|
| Category | Inflammatory |
| Compared against | RA vs healthy (established inflammatory pathway/drug target) |
| Test type | Blood test (serum / plasma / whole blood) |
| LOINC code | 26881-5 |
| Source | Qin et al. 2022 — doi:10.1136/ard-2022-222605 |
| Condition atlas | Rheumatoid Arthritis Biomarker Atlas |
Other conditions where Interleukin-6 (IL-6) is reported
- Interleukin-6 (IL-6) in Gulf War Illness — ↑ elevated vs HGV
- Interleukin-6 (IL-6) in Long COVID — ↑ elevated vs HC, R
- IL-6 in Low Back Pain — ↑ elevated vs chronic nonspecific LBP vs asymptomatic controls
- Interleukin-6 (IL-6) in Lyme Disease — ↑ elevated vs HC
- IL-6 in Major Depressive Disorder — ↑ elevated vs females with depression vs healthy female controls
- Interleukin-6 (IL-6) in ME/CFS — ↕ inconsistent vs HC
- IL-6 in PACVS — ↑ elevated vs HC
See the cross-condition hub: Interleukin-6 (IL-6) across conditions.
Related Inflammatory markers in Rheumatoid Arthritis
Full list: Rheumatoid Arthritis Biomarker Atlas.
Frequently asked questions
Is IL-6 high or low in Rheumatoid Arthritis?
Elevated. Studies summarised in the OSMF atlas report higher IL-6 in Rheumatoid Arthritis than in the reference group of the cited comparison (RA vs healthy (established inflammatory pathway/drug target)). Source: Qin et al. 2022.
Which test measures IL-6?
It is measured as a blood test (serum / plasma / whole blood). The standard laboratory code is LOINC 26881-5. Many of the cited studies used research-grade assays, so clinical availability may vary.
Is one abnormal IL-6 result diagnostic of Rheumatoid Arthritis?
No. No single biomarker is diagnostic of Rheumatoid Arthritis. IL-6 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 IL-6 specific to Rheumatoid Arthritis?
No. The same marker is also reported in Gulf War Illness, Long COVID, Low Back Pain, Lyme Disease, ME/CFS, Major Depressive Disorder, 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: 2026-07-03 · Page generated from rheumatoid-arthritis.json · Browse: Rheumatoid Arthritis 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.