AsseyMethod: Chemiluminescence
Abbrevation: C-peptide
Sector: Hormone 1
SampleType: S
S.Vol: 0.5
Transport: -20˚c
Storage: Immediately at -20 ˚c - up to Analyse
Test Name: Connecting Peptide, Insulin C- Peptide
Normal Range: 0.9-7.1
To monitor insulin production by the beta cells in the pancreas and to help determine the cause of hypoglycaemia (low blood sugar)
If you have diabetes mellitus and your doctor wants to see if you are producing any of your own insulin, if you are thought to be insulin resistant (when your body does not respond properly to insulin), or to help establish if it is time to add insulin injections to your current treatment. Your doctor also may request a C-peptide blood test if you have an episode of low blood sugar, called hypoglycaemia.
A blood sample taken from a vein in your arm and sometimes a 24-hour urine sample is taken
Fasting for 8 to 10 hours before blood testing is usually required.
This test measures the amount of C-peptide in a blood or urine sample. C-peptide and the hormone insulin are created from a larger molecule called proinsulin, and stored in the beta cells of the pancreas. When insulin is released into the bloodstream to help transport glucose into the body's cells (to be used for energy), equal amounts of C-peptide also are released. This makes C-peptide useful as a marker of insulin production and indeed better in some cases than insulin as it is more stable in the blood.
C-peptide can be used to help evaluate the production of endogenous insulin (insulin made by the body's beta cells) and to help differentiate it from exogenous insulin (insulin that is not produced by the body, e.g. injected insulin). This differentiation can be used to help diagnose and monitor a variety of conditions.
How is the sample collected for testing?
A blood sample is obtained by inserting a needle into a vein in the arm. If a 24-hour urine sample is required, you will be asked to save all of your urine over a 24 hour time period.
Is any test preparation needed to ensure the quality of the sample?
Fasting for 8 to 10 hours before blood testing is usually required.