ArticleDiabetic medicine : a journal of the British Diabetic Association2022
How low is really low? Comparison of two C-peptide assays to establish residual C-peptide production in type 1 diabetes.
Article in Diabetic medicine : a journal of the British Diabetic Association, 2022. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 6 papers.
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Who cites it
6 citing papers in PubMed, 13 citations in OpenAlex.
- C-peptide as an important biomarker in diabetes management: The need for standardization of its measurement.Diabetes, obesity & metabolism · 2026Article
- A CD40-targeting peptide, OPT501, modulates inflammation in canine diabetes mellitus improving clinical outcomes.Frontiers in immunology · 2026Article
- Article
- Fasting and meal-stimulated serum C-peptide in long-standing type 1 diabetes mellitus.Diabetic medicine : a journal of the British Diabetic Association · 2023Article
- How low is really low? Comparison of two C-peptide assays to establish residual C-peptide production in type 1 diabetes.Diabetic medicine : a journal of the British Diabetic Association · 2022Article
- Which C-peptide assay do you use? Increasing need for describing C-peptide assay performance.Pediatric endocrinology, diabetes, and metabolism · 2022Article
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Authors and funding
10 authors at 3 institutions in 3 countries.
Funding
No grant is acknowledged in the PubMed record.
Abstract
introductionC-peptide is an important marker to assess residual insulin production in individuals with type 1 diabetes (T1D). The accuracy and detection limits of C-peptide assays are important to detect C-peptide microsecretion and to reliably observe changes over time in these people. We compared and verified two commercially available assays able to measure C-peptide in the picomolar range.
methodsThe ultrasensitive Mercodia enzyme-linked immunosorbent C-peptide assay (ELISA) was compared with the Beckman immunoradiometric assay (IRMA) for C-peptide, assessing reproducibility (coefficient of variation [CV]), limit of blank (LoB), limit of detection (LoD) and limit of quantitation (LoQ).
resultsFor both assays within-run and between-run variation were high at the low (around the detection limit) C-peptide concentration range, with CVs of around 40%. LoB values for the ultrasensitive ELISA and the IRMA were 1.3 and 0.16 pmol/L respectively. LoD values were 2.4 and 0.54 pmol/L respectively. LoQ values were 9.7 and 3.8 pmol/L respectively. Only the IRMA met the specifications claimed by the manufacturer.
conclusionsThe IRMA provided the lowest threshold for quantification of serum C-peptide. LoQ of commercially available assays should be established in-house before applying them in research studies and clinical trials in which low C-peptide levels have clinical or scientific relevance.
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