What is the reference range for Connecting Peptide?

The standard reference range for Connecting Peptide is Fasting approximately 0.8–3.1 ng/mL (0.26–1.03 nmol/L); post-prandial or stimulated values higher.. Reference ranges vary by laboratory and assay platform — interpret in context of the issuing laboratory's stated range.

Which tests measure Connecting Peptide?

Connecting Peptide is measured in 1 test on BiomarkersLabs.com, including C-Peptide.

Biomarker Reference · C-peptide

What does the Connecting Peptide test measure?

Connecting Peptide (C-peptide) is a clinical biomarker used in metabolic-diabetes assessment. C-peptide is a 31-amino-acid cleavage product released in equimolar amounts with insulin when proinsulin is processed in pancreatic beta cells. It is measured in 1 laboratory test on BiomarkersLabs.com.

Reference Range: Fasting approximately 0.8–3.1 ng/mL (0.26–1.03 nmol/L); post-prandial or stimulated values higher.
Units: ng/mL, nmol/L
Measured In: 1 test
Category: Metabolic

Functional medicine optimalOptimal values are context-dependent: preserved or elevated C-peptide in the setting of diabetes suggests type 2 or monogenic disease with residual beta-cell function, while very low or undetectable fasting C-peptide confirms type 1 or late-stage insulin-deficient diabetes.

What is Connecting Peptide?

C-peptide is a 31-amino-acid cleavage product released in equimolar amounts with insulin when proinsulin is processed in pancreatic beta cells. Unlike insulin, it undergoes minimal hepatic first-pass extraction and has a longer plasma half-life of roughly 30 minutes, making it a more stable and direct indicator of endogenous insulin secretion. Because exogenous insulin preparations lack C-peptide, the assay distinguishes native beta-cell output from administered insulin.

Why is Connecting Peptide measured?

C-peptide is the gold-standard marker of endogenous insulin production. It resolves the critical question of whether hyperinsulinaemia is endogenous or exogenous, differentiates type 1 from type 2 diabetes and monogenic forms, guides insulin therapy decisions, investigates suspected insulinoma, and assesses beta-cell reserve in established diabetes. Its stability and independence from hepatic clearance make it superior to insulin measurement in many contexts.

Reference ranges

Standard reference: Fasting approximately 0.8–3.1 ng/mL (0.26–1.03 nmol/L); post-prandial or stimulated values higher.
Functional medicine optimal: Optimal values are context-dependent: preserved or elevated C-peptide in the setting of diabetes suggests type 2 or monogenic disease with residual beta-cell function, while very low or undetectable fasting C-peptide confirms type 1 or late-stage insulin-deficient diabetes.
Units: ng/mL, nmol/L

Reference ranges vary by laboratory and assay platform. Interpret in context of the issuing laboratory's stated range.

Tests that measure Connecting Peptide

1 test on BiomarkersLabs.com include this biomarker.

BML-MET-022Comprehensive

C-Peptide

Connecting Peptide reference range in this test: Fasting approximately 0.8–3.1 ng/mL (0.26–1.03 nmol/L); post-prandial or stimulated values higher.

Related clinical conditions

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