Order C-Peptide Blood Test from JustLabs for $10 ($28 all-in for a single-test order: $10 + one $18 lab & physician order fee per order). Price includes lab processing at Quest Diagnostics. No insurance required.
C-Peptide is a byproduct of insulin production that provides a reliable measure of how much insulin your pancreas is making, helping to classify diabetes type and assess beta cell function.
C-Peptide is a protein fragment that is released into the bloodstream when the pancreas produces insulin. For every molecule of insulin made, one molecule of C-Peptide is created. Because C-Peptide is cleared from the body more slowly than insulin and is not affected by insulin injections, it provides a more stable and accurate measurement of endogenous (your own) insulin production. This test is particularly valuable for distinguishing between Type 1 diabetes (where insulin production is minimal or absent) and Type 2 diabetes (where insulin may be normal or elevated but less effective). It can also help assess remaining beta cell function in people with diabetes and evaluate unexplained low blood sugar.
Price
$10
All-in
$28
incl. $18 lab & physician fee
Results
2-3 business days
Fasting
8+ hrs
What's Measured
What This Test Measures
This test measures the level of C-Peptide in your blood. C-Peptide levels directly reflect how much insulin your pancreas is producing. Low levels indicate reduced insulin production (as in Type 1 diabetes), while normal or high levels suggest adequate insulin production (as in early Type 2 diabetes or insulin resistance).
Who Should Consider This Test
People with newly diagnosed diabetes to determine type (Type 1 vs Type 2), those with Type 2 diabetes to assess if insulin therapy is needed, people with hypoglycemia to determine if it is caused by excess insulin production, and individuals with Type 1 diabetes to evaluate remaining beta cell function.
Health Insights
Conditions Screened
Related Symptoms
When to Get Tested
Fasting for 8-12 hours is required for accurate results. A fasting C-Peptide reflects baseline insulin production. Sometimes a stimulated C-Peptide test (after a meal or glucose drink) may be ordered to assess maximum insulin capacity.
Fasting Required
This test requires fasting for accurate results. Please follow these instructions:
- Do not eat or drink anything except water for 8-12 hours before your blood draw.
- Water is allowed and encouraged - stay hydrated!
- Schedule your lab visit in the morning for convenience.
- Continue taking any prescribed medications unless advised otherwise by your doctor.
Understanding Your Results
Normal fasting C-Peptide levels typically range from 0.5-2.0 ng/mL. Very low or undetectable levels (<0.2 ng/mL) strongly suggest Type 1 diabetes or advanced Type 2 diabetes with beta cell failure. Normal or elevated levels with high blood sugar suggest insulin resistance (Type 2 diabetes). Very high levels may indicate insulinoma or other insulin-secreting conditions.
What to Expect
After placing your order, we send it straight to Quest Diagnostics — there is no consent form to sign and no partner email to wait for. Your requisition is usually ready to download from your dashboard within about an hour, and you can book your blood draw at any Quest Diagnostics location.
The blood draw typically takes just a few minutes. Results are usually available within 2-3 business days and will appear in your secure JustLabs dashboard.
Our results include reference ranges and easy-to-understand indicators showing whether your values are within normal limits.
How much does the C-Peptide test cost?
The C-Peptide test costs $10 at JustLabs — $28 all-in, since the $18 lab & physician order fee is charged once per order, however many tests you add. The price is fixed before your blood draw; no insurance or doctor visit needed.
| Option | Price | Order all-in | Notes |
|---|---|---|---|
| C-Peptide at JustLabsDrawn at Quest Diagnostics | $10 | $28 | Includes the one $18 fee, charged once per order |
Paying with an HSA or FSA? See which lab tests qualify
Frequently Asked Questions
Hospital cash price: $150–$250
$10
+ $18 order fee · $28 all-inOne $18 fee per order covers your Quest blood draw and the independent physician order, however many tests you add.
- Results in 2-3 business days
- Fasting required (8 hours)
- Physician order included
No insurance needed · HSA/FSA eligible
- Physician-ordered
- CLIA-certified Quest lab
- Drawn at Quest Diagnostics
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