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C-Peptide, Serum from Marek Health

Labbrary Test GradeUseful
Your Fit Score
Not calculated

Answer five questions to see how this panel matches your goals, budget, collection preferences, access, and support needs.

Calculate my fit

Labbrary's review, Fit Score, and basic comparison are free. The provider's panel, shipping, collection, clinician review, and other services are separate. About 2 minutes. No account required.

Measure C-peptide to assess how much insulin your pancreas produces, including when you use injected insulin.

Current price
$26 $36 with fees
Sample
Blood
Turnaround
14 days
Access
Direct Lab, Lab Visit, Order Online
Evidence & Key Facts
Source collectedLast source check September 9, 2026

Evidence basis. This named result reflects the sources and verification evidence listed on this page as of the date shown.

Best for

Blood Sugar, Insulin Resistance

Standout strength

C-peptide is released by the pancreas alongside insulin.

Important watch-out

Marek adds a $10 venipuncture fee to orders of $199 or less and waives it on orders over $199. No additional payment is required at the lab. Lab sales are final and non-refundable.

C-Peptide, Serum from Marek Health
Labbrary Test GradeUseful
Your Fit Score
Not calculated

Answer five questions to see how this panel matches your goals, budget, collection preferences, access, and support needs.

Calculate my fit

Labbrary's review, Fit Score, and basic comparison are free. The provider's panel, shipping, collection, clinician review, and other services are separate. About 2 minutes. No account required.

Measure C-peptide to assess how much insulin your pancreas produces, including when you use injected insulin.

Current price
$26 $36 with fees
Sample
Blood
Turnaround
14 days
Access
Direct Lab, Lab Visit, Order Online
Evidence & Key Facts
Source collectedLast source check September 9, 2026

Evidence basis. This named result reflects the sources and verification evidence listed on this page as of the date shown.

Best for

Blood Sugar, Insulin Resistance

Standout strength

C-peptide is released by the pancreas alongside insulin.

Important watch-out

Marek adds a $10 venipuncture fee to orders of $199 or less and waives it on orders over $199. No additional payment is required at the lab. Lab sales are final and non-refundable.

Labbrary+

The Test Grade. The Reason Behind It.

Potentially useful for the right buyer, with meaningful evidence, coverage, transparency, access, cost, terms, or privacy tradeoffs to review.

A lower grade does not mean a panel is a bad personal fit. Your Fit Score can be higher when its purpose, price, sample, access, or support matches what you need.

Explore the Full Methodology
Labbrary Test GradeUseful

Next step

Check the panel or research the provider

Prices, availability, and ordering requirements can change. Confirm the current details before purchasing.

View Exact Panel on Provider SiteView Marek Health profile

Scope, both directions

Inside the Panel. Beyond the Name.

Named measurements

  • C-Peptide, Serum

Measured categories and focus areas

  • Metabolic Health
  • Blood Sugar
  • Insulin Resistance

Important limits and omissions

  • Serum C-peptide is the named measurement. The exact analytical method, performing laboratory, assay validation and specimen-handling requirements have not been established.
  • The named scope is C-peptide alone. A glucose result, insulin measurement and broader diabetes panel are not listed as included. Sufficiency for an individual's beta-cell or metabolic assessment has not been evaluated.
  • Results are emailed when available. Guided Optimization is a separate program with treatment eligibility requirements. An included consultation, individual interpretation service, actual sample report, reference-range explanation and follow-up plan have not been established for this test purchase.
  • Comparative value and clinical data or specimen privacy have not been fully assessed.

No broader panel in the Labbrary catalog lists every biomarker on this one for a lower listed price.

Counted among one-time lab-draw listings with a published price, matched by published biomarker names. That doesn’t mean the tests are equivalent. Updated October 2, 2026.

The full breakdown

Eight Dimensions.
One Named Result.

Open any row for the reasoning and evidence behind the named result.

Seller is Marek Diagnostics; the ordering clinician is Marek-arranged (provider reviews and approves test requests; no buyer clinician visit required) where stated. Collection route is the Quest Diagnostics laboratory system. A Quest draw location or the Marek relationship does not prove the exact performing facility, the assay method, or offer-specific analytical performance, which remain unpublished. Limitation: Seller is Marek Diagnostics; the ordering clinician is Marek-arranged (provider reviews and approves test requests; no buyer clinician visit required) where stated. Collection route is the Quest Diagnostics laboratory system. A Quest draw location or the Marek relationship does not prove the exact performing facility, the assay method, or offer-specific analytical performance, which remain unpublished.

Exact named measurement scope per the product page title and description. Limitation: No additional limitation was recorded in the authority row.

Named analytes per the exact offer; panel boundaries per the product page. Limitation: No additional limitation was recorded in the authority row.

Result delivery format partially documented. Limitation: No additional limitation was recorded in the authority row.

Exact price, purchase route, and ordering model on the product page; performing lab assignment unpublished. Limitation: No additional limitation was recorded in the authority row.

Online ordering with provider-approved test requests; Quest collection; state restrictions apply. Limitation: No additional limitation was recorded in the authority row.

Exact-offer price on the product page; refund and draw-fee terms per shared policies. Limitation: No additional limitation was recorded in the authority row.

Shared Marek privacy policy governs order data; specimen and result retention unresolved. Limitation: No additional limitation was recorded in the authority row.

What it asks of you

Sample and fulfillment journey

Order

Confirmed

Order C-Peptide, Serum online for $26 before any checkout fees. Healthcare-provider review and approval is arranged without an office visit.

Panel-specific source · Source dated September 9, 2026

Collect

Confirmed

Order online for healthcare-provider review and approval, then provide a blood sample at a Quest location. No healthcare-provider office visit is required. Confirm preparation and collection instructions for this exact test.

Panel-specific source · Source dated September 9, 2026

Lab

Confirmed

Results typically arrive within 14 business days. Approximately two weeks is a general estimate that varies with test size and complexity; it is not a guaranteed calendar-day deadline. The exact laboratory performing the assay has not been independently identified.

Panel-specific source · Source dated September 9, 2026

Report

Partially confirmed

Results are emailed when available. Guided Optimization is a separate program with treatment eligibility requirements. An included consultation, individual interpretation service, actual sample report, reference-range explanation and follow-up plan have not been established for this test purchase.

Panel-specific source · Source dated September 9, 2026

Under the hood

Follow the Evidence.

Every published claim should trace to a dated source. Missing evidence remains visible instead of being filled with assumptions.

Source 1Recorded for this record. Last source check September 9, 2026.View source
Source 2Recorded for this record. Last source check September 9, 2026.View source
Source 3Recorded for this record. Last source check September 9, 2026.View source
Source 4Recorded for this record. Last source check September 9, 2026.View source
Source 5Recorded for this record. Last source check September 9, 2026.View source
Source 6Recorded for this record. Last source check September 9, 2026.View source
Source 7Recorded for this record. Last source check September 9, 2026.View source
Source 8Recorded for this record. Last source check September 9, 2026.View source

True total cost

The Price. Plus the Details.

Pricing for C-Peptide, Serum
ItemCurrent disclosed priceNote
Panel$26Verify the checkout total, shipping, and collection fees before ordering.
Venipuncture fee+ $10Per order, added at checkout. Checked October 1, 2026. Source
Total at checkout$36Listed price plus the required fees above, before tax and any optional services.
HSA/FSA paymentNot confirmedHSA/FSA payment eligibility has not been confirmed from provider documentation.
Optional servicesNot confirmedClinician review, subscriptions, and retesting discounts are listed only when documented.

Price status. This record shows disclosed pricing. Checkout costs can change and should be verified before purchase.

Your data

Your Data. Your Questions.

Privacy details are scored only when source documentation is available. Unconfirmed retention, deletion, research use, or marketing practices remain unconfirmed.

Reading the labels

What Has Been Checked?

Source collected

Evidence labels stay separate from the Test Grade. They show how much source support exists for the evaluation.

The balance

The Strengths. The Tradeoffs.

Strengths

  • C-peptide is released by the pancreas alongside insulin.
  • Order online for provider approval and blood collection at Quest.
  • The lab requisition is valid for six months from purchase.

Watch-outs

  • Marek adds a $10 venipuncture fee to orders of $199 or less and waives it on orders over $199. No additional payment is required at the lab. Lab sales are final and non-refundable.
  • Eligible US residents need a valid US driver license or state-issued ID. Hawaii and US territories are excluded, and orders are unavailable to residents of New York, New Jersey and Rhode Island. Massachusetts buyers should confirm that the collection site accepts the order before paying.
  • Results typically arrive within 14 business days. Approximately two weeks is a general estimate that varies with test size and complexity; it is not a guaranteed calendar-day deadline.
  • Serum C-peptide is the named measurement. The exact analytical method, performing laboratory, assay validation and specimen-handling requirements have not been established.
  • The named scope is C-peptide alone. A glucose result, insulin measurement and broader diabetes panel are not listed as included. Sufficiency for an individual's beta-cell or metabolic assessment has not been evaluated.
  • Results are emailed when available. Guided Optimization is a separate program with treatment eligibility requirements. An included consultation, individual interpretation service, actual sample report, reference-range explanation and follow-up plan have not been established for this test purchase.

Take it with you

The Test Truth Card

The key facts from this review in one compact card.

Same biomarkers, other sellers

Other Ways to Buy This Test.

1 other listing in the Labbrary catalog publishes this exact biomarker list, with a lab draw.

C-Peptide Blood Test

Mito Health

Useful

Measures C-peptide to assess your own pancreatic insulin production when investigating diabetes type, remaining beta-cell function or unexplained low blood sugar. Order online for a fasting partner-laboratory blood draw and clinician-guided interpretation.

Price
$18.15
Turnaround
1 day
See Labbrary reviewView Exact Panel on Provider Site
Labbrary+

Listed prices from the Labbrary catalog. Some sellers add fees at checkout, so compare the total before you pay. Updated October 2, 2026.

Keep deciding

Fasting Insulin Test

Health Testing Centers

Limited

Uses a blood sample to assess the published metabolic health scope, with exact measurements and ordering details listed separately.

Price
$29
Turnaround
Not confirmed
See Labbrary reviewView Exact Panel on Provider Site
Labbrary+

Insulin and C-Peptide Panel

Mito Health

Useful

Measures insulin and C-peptide together to show how much insulin your body is producing and how your pancreatic beta cells are working.

Price
$36.57
Turnaround
2 days
See Labbrary reviewView Exact Panel on Provider Site
Labbrary+

Insulin (Fasting Insulin)

Marek Health

Useful

Measure fasting insulin to assess how much insulin is circulating while fasted and add information about possible insulin resistance to your metabolic review.

Price
$10
Turnaround
14 days
See Labbrary reviewView Exact Panel on Provider Site
Labbrary+
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Verification History

September 9, 2026Recorded source date.Source collected

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