The C-peptide level is measured by taking the blood or urine sample to find how much our body makes insulin. Beta cells of the pancreas, secrete a substance called C-peptide along with insulin. Both C-peptide and insulin are released in about equal amounts at the same time. And, C-peptide stays in the body for a longer time than insulin. Therefore, measuring the C-peptide level can determine the level of insulin present in your body, which helps in diabetes treatment. Insulin controls the blood sugar levels whereas C-peptide level does not affect blood sugar.
Why to consider C-peptide test?
C-peptide test can find out –
- How much insulin your pancreas is making when you have type 1 diabetes. And then, the physician can decide how much insulin treatment should be given to treat type 1 diabetes
- Whether a person has type 1 diabetes or type 2 diabetes
- The difference between insulin that body makes and the insulin given by injecting into the body
- The cause of your low blood sugar (hypoglycemia)
- Insulin-producing tumor of the pancreas (insulinoma)
- The correct time to start insulin in a patient with type 2 diabetes
- How well your treatment is working if you have diabetes
Let us understand the results of a C-peptide test.
- A normal C-peptide level is 0.5 to 2.0 nanograms per milliliter
- If the C-peptide level is more than the normal value, it indicates your body is making more insulin than usual
- If the C-peptide level is less than the normal value, it indicates your body is making little or no insulin
Reasons for high C-peptide level in the body:
- Your body is insulin resistant or may have type 2 diabetes
- You may have a tumor known as insulinoma
- Kidney disease
- Have taken an excess of a certain class of drugs (sulfonylureas) to treat diabetes
Reasons for low C-peptide level in the body:
- You may have type 1 diabetes
- You are on insulin injection and it is suppressing the release of insulin from your pancreas
- Have a poorly functioning pancreas
- You may have liver disease or have taken insulin therapy
- You’ve had your pancreas removed
Before going for the C-peptide test, ask your doctor whether you need to fast or stop medication for diabetes. Because the timing of your most recent meal taken and medications can affect the C-peptide level.