---
title: C-Peptide Test
type: biomarker
url: "https://www.test-well.com/biomarkers/c-peptide"
also_known_as:
  - c-peptide
  - c peptide
  - connecting peptide
category: Diabetes & Blood Sugar
units:
  - ng/mL
order_price_usd: 29.99
order_item: C-Peptide
order_url: "https://www.test-well.com/tests/c-peptide-test"
reviewed_at: 2026-09-05
---

# C-Peptide

> C-Peptide is measured with a standard blood draw after an 8–12 hour fast. A typical reference range is 1.10 – 4.40 ng/mL. At TestWell it's $29.99 all-in as C-Peptide, results in 2–4 business days, drawn at Labcorp. An out-of-range result is a prompt to look closer, not a diagnosis.

Also known as: c-peptide, c peptide, connecting peptide.

## Key facts

| Fact | Value |
| --- | --- |
| Units | ng/mL |
| Sample | Blood draw |
| Fasting | 8–12 hours |
| Results | 2–4 business days |
| Price | $29.99 |
| Labs | Labcorp |

## What does C-Peptide measure?

A byproduct of insulin production. Reflects how much insulin your pancreas is making, not how much you've injected.

## What is the normal range for C-Peptide?

| Population | Reference range |
| --- | --- |
| age 18+ | 1.10 – 4.40 ng/mL |

Reference intervals differ slightly between labs; the range printed on your report is the one to interpret against. Ranges are usually set so 95% of healthy people fall inside them.

## How do you get tested for C-Peptide?

| Order | Type | Price | Includes |
| --- | --- | --- | --- |
| [C-Peptide](https://www.test-well.com/tests/c-peptide-test) | Single test | $29.99 | This marker |
| [Pre-Diabetes Panel](https://www.test-well.com/tests/pre-diabetes-panel) | Panel | $89.99 | 5 tests |
| [Total Body Panel](https://www.test-well.com/tests/total-body-panel) | Panel | $499.99 | 49 tests |

## Quest vs Labcorp vs BioReference

| Lab | Available | Price | Notes |
| --- | --- | --- | --- |
| Quest Diagnostics | No | — | Not offered through Quest for this test. |
| Labcorp | Yes | $29.99 | Choose Labcorp at checkout; walk-in patient service centers in every state TestWell serves outside NY and NJ. |
| BioReference (NY & NJ) | No | — | Not available in NY/NJ for this test. |

- [What a high C-Peptide means (causes, symptoms, next steps)](https://www.test-well.com/biomarkers/c-peptide/high)
- [What a low C-Peptide means (causes, symptoms, next steps)](https://www.test-well.com/biomarkers/c-peptide/low)

## Common questions about C-Peptide

### Do I need a doctor's order to test my c-peptide?

No. TestWell's licensed physician network reviews and approves your order — usually within minutes. You can place an order online without an in-person visit or a referral from your own doctor.

### How long does it take to get C-Peptide results?

Most C-Peptide results are available in 1–3 business days after your specimen arrives at the lab. You'll get an email the moment your results are ready, with everything viewable in your TestWell portal.

### How much does a C-Peptide test cost?

Our C-Peptide starts at $29.99. That's the all-in price — no copays, no insurance hoops, no surprise bills. HSA and FSA cards are accepted.

### Do I need to fast before my C-Peptide test?

Yes — for the most accurate result, fast for 8–12 hours before your blood draw. Water is fine; coffee, food, and supplements are not. Your prep instructions will be included with your order.

### Which lab will process my C-Peptide test?

Your test will be processed by Quest Diagnostics, Labcorp, or BioReference depending on which is closest to you and which lab carries the test. All three are CLIA-certified and trusted by hospitals nationwide. You'll choose your lab during checkout from 4,000+ locations.

## Sources

- [Mayo Clinic Labs](https://www.mayocliniclabs.com/test-catalog/overview/8460)
- [MedlinePlus (NIH) — C-Peptide Test](https://medlineplus.gov/lab-tests/c-peptide-test/)

## Related biomarkers

- [Hemoglobin A1c](https://www.test-well.com/biomarkers/hemoglobin-a1c)
- [Fasting Insulin](https://www.test-well.com/biomarkers/fasting-insulin)

- [Reference range lookup tool](https://www.test-well.com/tools/reference-range-lookup)
- [Lab unit converter](https://www.test-well.com/tools/lab-unit-converter)
- [All biomarkers](https://www.test-well.com/biomarkers)

---

Medically reviewed by Youmna DiStefano, MD (Medical Reviewer, TestWell); last reviewed 2026-09-05. Review policy: https://www.test-well.com/reviewers/youmna-distefano-md

Canonical page: https://www.test-well.com/biomarkers/c-peptide
Machine-readable catalog: https://www.test-well.com/api/catalog.json · MCP server: https://www.test-well.com/mcp · Overview for agents: https://www.test-well.com/llms.txt

Prices are cash-pay, in USD, and include physician authorization; every order adds one flat $6 lab processing fee. Educational content is not a diagnosis — discuss results with a clinician.