Days Set Up
Monday, Wednesday, Friday
Analytic Time

8 hours

MiChart Code
Soft Order Code

Test Updated:


Connecting Peptide
C-Peptide Reactivity
Endogenous Insulin, Marker
Insulin C-Peptide

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Find a Requisition

All specimens should be accompanied by a requisition.

Submitting Specimens

Learn about how to properly label and where to ship specimens.

Order Kits and Supplies

MLabs provides all the supplies necessary for the collection of specimens.

Test FAQ

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Test Overview

Test Methodology


Test Usage

Evaluate residual beta cell function in patients with diabetes mellitus treated with insulin, low in instances of surreptitious injection of insulin, elevated in insulin autoimmune hypoglycemia, workup of hypoglycemia and to aid in the diagnosis of insulinoma with glucose and insulin assays.

Reference Range

1.0-5.2 ng/ml (fasting)

* Reference ranges may change over time. Please refer to the original patient report when evaluating results.

Specimen Requirements

Collection Offsite

Collect specimen in green top tube from a fasting patient (red top tube is acceptable). Place specimen on ice immediately after collection and keep cold until ready to aliquot. Centrifuge, aliquot plasma into a plastic vial and freeze within 1 hour of collection.

Normal Volume
1 mL plasma
Minimum Volume
0.5 mL plasma

Billing Information

CPT Code
Pro Fee Code

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Our High Standard

Quality that sets us apart

As the reference laboratory division of Michigan Medicine's Department of Pathology, MLabs shares the institution's commitment to applying established quality principles to clinical laboratory testing. Like other large organizations in complex, consequential fields, we rely on an established approach to monitor quality throughout the testing process.