Research Tracker›Biomarker Atlas›Long COVID›Amyloid-fibrin microclots

Amyloid-fibrin microclots in Long COVID

Amyloid-fibrin microclots, also described as Fibrin(ogen) amyloid deposits, is a coagulation marker reported as elevated in Long COVID (PASC, Post-Acute Sequelae of COVID-19) when patients are compared with healthy controls. Symptom domains tied to this marker in the source include microvascular occlusion, hypoperfusion. This entry summarises Pretorius et al. 2023. Group-level associations like this do not translate into an individual diagnostic cut-off.

↑ ElevatedCoagulation

Summary

Direction in Long COVID↑ Elevated — higher than in the comparison group
CategoryCoagulation
Also described asFibrin(ogen) amyloid deposits
Compared againstHC (healthy controls)
Associated symptomsMicrovascular occlusion, hypoperfusion
Test typeBlood test (serum / plasma / whole blood)
SourcePretorius et al. 2023 — doi:10.1186/s12933-023-01931-4
Condition atlasLong COVID Biomarker Atlas

Related Coagulation markers in Long COVID

Full list: Long COVID Biomarker Atlas.

Frequently asked questions

Is Amyloid-fibrin microclots high or low in Long COVID?

Elevated. Studies summarised in the OSMF atlas report higher Amyloid-fibrin microclots in Long COVID than in healthy controls. Source: Pretorius et al. 2023.

What symptoms is Amyloid-fibrin microclots associated with in Long COVID?

The cited literature associates this marker with Microvascular occlusion, hypoperfusion. These are population-level associations and do not mean the marker causes the symptoms.

Which test measures Amyloid-fibrin microclots?

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 Amyloid-fibrin microclots result diagnostic of Long COVID?

No. No single biomarker is diagnostic of Long COVID. Amyloid-fibrin microclots 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). Amyloid-fibrin microclots in Long COVID: direction, evidence and what it means. OSMF Research Tracker. Retrieved October 7, 2026, from https://research.opensourcemed.info/biomarkers/long-covid/amyloid-fibrin-microclots.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.