Summary
| Direction in Long COVID | ↕ Inconsistent — reported as both higher and lower across studies, with no consistent direction |
|---|---|
| Category | Microbiome |
| Also described as | Butyrate, propionate, acetate |
| Compared against | HC (healthy controls) |
| Associated symptoms | GI and metabolic symptoms |
| Test type | Blood test (serum / plasma / whole blood) |
| Source | Baalbaki et al. 2025 — doi:10.1111/all.16526 |
| Condition atlas | Long COVID Biomarker Atlas |
Trials, interventions and tests
In clinical-trial registrations this marker maps to the outcome term Difference in plasma short chain fatty acid (SCFA) levels between study arms (1 registered trials use a matching outcome measure).
Clinical trials using Short-chain fatty acids (SCFAs) as an outcome
- NCT06620406: Synbiotic Therapy for NP-PASC (Completed)
Outcome measure: Difference in plasma short chain fatty acid (SCFA) levels between study arms
Also sold as a nutrient or supplement
Short-chain fatty acids / Butyrate (supplement). Postbiotic and fiber-derived SCFA supplements. This tag means the analyte is also available orally; it is not a product endorsement and a low or high level does not by itself justify supplementation.
Related Microbiome markers in Long COVID
Full list: Long COVID Biomarker Atlas.
Frequently asked questions
Is Short-chain fatty acids (SCFAs) high or low in Long COVID?
Mixed. Some studies report higher and others lower Short-chain fatty acids (SCFAs) in Long COVID compared with healthy controls, so no single direction is established. Source: Baalbaki et al. 2025.
What symptoms is Short-chain fatty acids (SCFAs) associated with in Long COVID?
The cited literature associates this marker with GI and metabolic symptoms. These are population-level associations and do not mean the marker causes the symptoms.
Which test measures Short-chain fatty acids (SCFAs)?
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 Short-chain fatty acids (SCFAs) result diagnostic of Long COVID?
No. No single biomarker is diagnostic of Long COVID. Short-chain fatty acids (SCFAs) 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.