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C-Peptide in Type 1 Diabetes

C-Peptide is a metabolic marker reported as reduced in Type 1 Diabetes when patients are compared with the reference group of the cited comparison (long-duration T1D vs healthy/normal reference range). The source does not tie this marker to a specific symptom cluster, so it is best read as a biological signal rather than a symptom predictor. This entry summarises Yu et al. 2019. Group-level associations like this do not translate into an individual diagnostic cut-off.

↓ ReducedMetabolic

Summary

Direction in Type 1 Diabetes↓ Reduced — lower than in the comparison group
CategoryMetabolic
Compared againstlong-duration T1D vs healthy/normal reference range
SourceYu et al. 2019 — doi:10.1172/JCI127397
Condition atlasType 1 Diabetes Biomarker Atlas

Related Metabolic markers in Type 1 Diabetes

Full list: Type 1 Diabetes Biomarker Atlas.

Frequently asked questions

Is C-Peptide high or low in Type 1 Diabetes?

Reduced. Studies summarised in the OSMF atlas report lower C-Peptide in Type 1 Diabetes than in the reference group of the cited comparison (long-duration T1D vs healthy/normal reference range). Source: Yu et al. 2019.

Which test measures C-Peptide?

The atlas record does not list a standardised clinical test code (LOINC) for C-Peptide, which usually means it was measured with research assays or study-specific protocols rather than a routine clinical panel. Check the cited source for the exact method.

Is one abnormal C-Peptide result diagnostic of Type 1 Diabetes?

No. No single biomarker is diagnostic of Type 1 Diabetes. C-Peptide 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). C-Peptide in Type 1 Diabetes: direction, evidence and what it means. OSMF Research Tracker. Retrieved October 7, 2026, from https://research.opensourcemed.info/biomarkers/type-1-diabetes/c-peptide.html
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Last reviewed: 2026-07-03 · Page generated from type-1-diabetes.json · Browse: Type 1 Diabetes 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.