Research Tracker›Biomarker Atlas›Long COVID›Acute phase proteins

Acute phase proteins in Long COVID

In Long COVID (PASC, Post-Acute Sequelae of COVID-19), published studies report higher levels of Acute phase proteins, also described as AGP, haptoglobin, orosomucoid, than in healthy controls. Symptom domains tied to this marker in the source include systemic inflammation. The evidence summarised here comes from Baalbaki et al. 2025 and reflects averages across cohorts rather than any single patient's result.

↑ ElevatedProteomic

Summary

Direction in Long COVID↑ Elevated — higher than in the comparison group
CategoryProteomic
Also described asAGP, haptoglobin, orosomucoid
Compared againstHC (healthy controls)
Associated symptomsSystemic inflammation
Test typeBlood test (serum / plasma / whole blood)
SourceBaalbaki et al. 2025 — doi:10.1111/all.16526
Condition atlasLong COVID Biomarker Atlas

Related Proteomic markers in Long COVID

Full list: Long COVID Biomarker Atlas.

Frequently asked questions

Is Acute phase proteins high or low in Long COVID?

Elevated. Studies summarised in the OSMF atlas report higher Acute phase proteins in Long COVID than in healthy controls. Source: Baalbaki et al. 2025.

What symptoms is Acute phase proteins associated with in Long COVID?

The cited literature associates this marker with Systemic inflammation. These are population-level associations and do not mean the marker causes the symptoms.

Which test measures Acute phase proteins?

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 Acute phase proteins result diagnostic of Long COVID?

No. No single biomarker is diagnostic of Long COVID. Acute phase proteins 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.

Cite this page

Open Source Medicine Foundation. (2026). Acute phase proteins in Long COVID: direction, evidence and what it means. OSMF Research Tracker. Retrieved October 7, 2026, from https://research.opensourcemed.info/biomarkers/long-covid/acute-phase-proteins.html
Get OSMF research updates. New biomarker, trial and treatment evidence summaries by email.
Subscribe on Substack

Last reviewed: 2026-06-29 · Page generated from long-covid.json · Browse: Long COVID 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.