C-Peptide and Fructosamine

I just spoke to my endo’s office. They did a blood test and my c-peptide is 2.4 and fructosamine is 237.
What do those numbers mean? The nurse who called me said that my doctor will discuss the results with me at my next appointment, 4 weeks from now.

The C-Peptide and fructosamine are both normal.

Approximate Comparison of Blood Glucose,
HbA1c , & Fructosamine Levels
Glucose (mg/dl) Fructosamine (µmol) HbA1c (%)
90 212.5 5.0
120 250 6.0
150 287.5 7.0
180 325 8.0
210 362.5 9.0
240 400 10.0
270 437.5 11.0
300 475 12.0
330 512.5 13.0
360 550 14.0
390 587.5 15.0

C-Peptice Ranges

Adults 8:00 a.m. fasting: 0.4 to 2.1 ng/ml

Two hours postprandial (after a meal): 1.2 to 3.4 ng/ml

Two hours post glucose load: 2.0 to 4.5 ng/ml

A positive C-peptide usually indicates that you are still making some insulin. Was your c-peptide level checked when you were fasting? Or was it postprandial? The typical ranges for c-peptide are :

Fasting: 0.4 to 2.1 ng/ml

2 hours postprandial : 1.2 to 3.4 ng/ml

Keep in mind that those with insulin resistance may gave normal to high c-peptide values because they make a lot of insulin.

Fructosamine is a good indicator of glycemic control over a duration of 2 to 3 weeks. Think of it as an A1C test, but in this case, it presents a picture of how good or bad BG control has been for a period of 2 to 3 weeks instead of the 6 to 8 weeks for A1C. A fructosamine value of 237 corresponds to an A1C of about 5.7.

Generally, a fructosamine is used in place of a glycosated hemoglobin (better known as hemoglobin A1C) to measure a shorter period of time and be indicative of your more recent metabolic control. Some doctors like to use the fructosamine test to measure how well a new or change in treatment is working, and with this test, they need not wait 90 days for the results to be available as they would with a hemoglobin A1C.

The test was done about 2 hours after lunch. I’m glad there is still some insulin being created. Thanks everyone for the help, this gives me some hope!