Summary
| Direction in Long COVID | ↑ Elevated — higher than in the comparison group |
|---|---|
| Category | Vascular |
| Also described as | Intercellular adhesion molecule |
| Compared against | HC (healthy controls) |
| Associated symptoms | Endothelial activation |
| Test type | Blood test (serum / plasma / whole blood) |
| Source | Thomas et al. 2024 — doi:10.1007/s40291-024-00731-z |
| Condition atlas | Long COVID Biomarker Atlas |
Related Vascular markers in Long COVID
- von Willebrand Factor (vWF) ↑
- VCAM-1 ↑
- Resistin ↑
- Endothelin-1 ↑
- Asymmetric dimethylarginine (ADMA) ↑
- NT-proBNP ↑
- Troponin ↑
Full list: Long COVID Biomarker Atlas.
Frequently asked questions
Is ICAM-1 high or low in Long COVID?
Elevated. Studies summarised in the OSMF atlas report higher ICAM-1 in Long COVID than in healthy controls. Source: Thomas et al. 2024.
What symptoms is ICAM-1 associated with in Long COVID?
The cited literature associates this marker with Endothelial activation. These are population-level associations and do not mean the marker causes the symptoms.
Which test measures ICAM-1?
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 ICAM-1 result diagnostic of Long COVID?
No. No single biomarker is diagnostic of Long COVID. ICAM-1 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.
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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.