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Complement C3a / C5a: biomarker evidence

Complement C3a / C5a appears in 1 entry of the OSMF biomarker atlas, covering Long COVID. Across those entries it is elevated in 1. It is currently reported in a single condition in this atlas; cross-condition comparison will be added as the dataset grows. Each row below links to a page with the comparison group, associated symptoms, test details and primary citation.

Long COVID

Where Complement C3a / C5a is reported

Also listed as: Anaphylatoxins

ConditionDirectionCompared againstAssociated symptomsSource
Long COVID↑ elevatedhealthy controlsComplement activationBaalbaki et al. 2025

Frequently asked questions

In which conditions is Complement C3a / C5a altered?

In the OSMF atlas Complement C3a / C5a is reported in Long COVID. It is elevated in 1 across 1 entries.

Is there a standard clinical test for Complement C3a / C5a?

The atlas entries for Complement C3a / C5a do not carry a LOINC code, which usually means the marker was measured with research assays or study-specific methods rather than a routine clinical panel.

Is one abnormal Complement C3a / C5a result diagnostic?

No single biomarker result is diagnostic of any of these conditions. Findings reflect group averages from published cohorts with substantial overlap between patients and controls.

Cite this page

Open Source Medicine Foundation. (2026). Complement C3a / C5a across conditions: biomarker evidence. OSMF Research Tracker. Retrieved October 7, 2026, from https://research.opensourcemed.info/biomarkers/markers/complement-c3a-c5a.html
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Last reviewed: 2026-06-29 · Browse: Biomarker Index · All marker pages · Biomarker Atlas

Disclaimer: Educational synthesis of peer-reviewed research; not medical advice. Findings are group-level and vary with study design. Discuss any result with a qualified clinician.