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C-Peptide (SI)

Order Code
1103175
CPT
84681
Test Details
Synonyms

Connecting Peptide of Insulin

TAT

Up to 24 hours

Methodology

Electrochemiluminesence Immunoassay (ECLIA)

Reference Interval

Results should be interpreted in the context of the clinical condition.

Remarks

See overview

Performing Location

Accredited NRL Laboratory

Testing Frequency

Daily

Test Overview

C-peptide is a valuable clinical marker of endogenous insulin production, as it is co-secreted with insulin from pancreatic beta cells. Unlike insulin, C-peptide is not extracted by the liver and has a longer half-life, making it a reliable indicator of beta-cell function. It helps differentiate between type 1 and type 2 diabetes, evaluate suspected insulinoma, and assess residual beta-cell activity in patients on insulin therapy. In hypoglycemia, elevated C-peptide suggests endogenous hyperinsulinism, while low levels indicate exogenous insulin use. C-peptide is also used to monitor pancreatic function in patients undergoing islet transplantation or with longstanding diabetes.

Specimen Type

Serum or Plasma (Li-Hep)

Volume

Minimum 0.5 mL

Specimen Container

Serum Separator Tube (SST; Gold Top), Plain Tube (Red Top), Lithium Heparin Plasma (Green Top)

Patient Preparation

No special preparation is required for this test. You may eat, drink, and take your medications as normal, unless instructed otherwise by your healthcare provider.

Collection

Samples should be sent to the laboratory as soon as possible after collection. If this is not possible, samples should be centrifuged and transported refrigerated (2 to 8°C).

Specimen Stability
Temperature Period
Refrigerated 24 hours
Frozen 1 month at -20° C
Order Code
1103175
CPT
84681
Test Details
Synonyms

Connecting Peptide of Insulin

TAT

Up to 24 hours

Methodology

Electrochemiluminesence Immunoassay (ECLIA)

Reference Interval

Results should be interpreted in the context of the clinical condition.

Remarks

See overview

Performing Location

Accredited NRL Laboratory

Testing Frequency

Daily

Test Overview

C-peptide is a valuable clinical marker of endogenous insulin production, as it is co-secreted with insulin from pancreatic beta cells. Unlike insulin, C-peptide is not extracted by the liver and has a longer half-life, making it a reliable indicator of beta-cell function. It helps differentiate between type 1 and type 2 diabetes, evaluate suspected insulinoma, and assess residual beta-cell activity in patients on insulin therapy. In hypoglycemia, elevated C-peptide suggests endogenous hyperinsulinism, while low levels indicate exogenous insulin use. C-peptide is also used to monitor pancreatic function in patients undergoing islet transplantation or with longstanding diabetes.

Specimen Type

Serum or Plasma (Li-Hep)

Volume

Minimum 0.5 mL

Specimen Container

Serum Separator Tube (SST; Gold Top), Plain Tube (Red Top), Lithium Heparin Plasma (Green Top)

Patient Preparation

No special preparation is required for this test. You may eat, drink, and take your medications as normal, unless instructed otherwise by your healthcare provider.

Collection

Samples should be sent to the laboratory as soon as possible after collection. If this is not possible, samples should be centrifuged and transported refrigerated (2 to 8°C).

Specimen Stability
Temperature Period
Refrigerated 24 hours
Frozen 1 month at -20° C