Research Tracker›Biomarker Atlas›Marker Pages›Cystatin D (CST5)

Cystatin D (CST5): biomarker evidence

Cystatin D (CST5) 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 Cystatin D (CST5) is reported

Also listed as: Protease inhibitor

ConditionDirectionCompared againstAssociated symptomsSource
Long COVID↑ elevatedNon-COVID controlsElevated at 6 months post-infectionKallaste et al. 2025

Frequently asked questions

In which conditions is Cystatin D (CST5) altered?

In the OSMF atlas Cystatin D (CST5) is reported in Long COVID. It is elevated in 1 across 1 entries.

Is there a standard clinical test for Cystatin D (CST5)?

The atlas entries for Cystatin D (CST5) 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 Cystatin D (CST5) 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). Cystatin D (CST5) across conditions: biomarker evidence. OSMF Research Tracker. Retrieved October 7, 2026, from https://research.opensourcemed.info/biomarkers/markers/cystatin-d-cst5.html
Get OSMF research updates. New biomarker, trial and treatment evidence summaries by email.
Subscribe on Substack

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.