From the Guidelines
C-peptide testing is a crucial tool for assessing pancreatic beta cell function in diabetes management, and it is used to check for diabetes, particularly to distinguish between type 1 and type 2 diabetes, as recommended by the most recent guidelines 1.
Importance of C-peptide Testing
C-peptide testing measures the amount of C-peptide, a protein fragment released when proinsulin is converted to insulin in the pancreas. This test helps determine the body's endogenous insulin production capacity, which is essential for making informed decisions about diabetes management approaches.
Key Points to Consider
- C-peptide levels can help differentiate between type 1 and type 2 diabetes, with low or absent levels typically indicating type 1 diabetes and normal or high levels suggesting type 2 diabetes 1.
- The test requires a blood sample and may be performed fasting or after a meal to evaluate the body's insulin response.
- Normal C-peptide levels generally range from 0.5 to 2.0 ng/mL when fasting, but these values can vary between laboratories.
- C-peptide testing is particularly useful when determining appropriate treatment strategies, such as whether insulin therapy is necessary or if other medications might be effective.
Clinical Application
In clinical practice, C-peptide testing is used to:
- Diagnose and classify diabetes
- Monitor pancreatic beta cell function
- Guide treatment decisions, such as insulin therapy or other medications
- Evaluate the effectiveness of treatment plans According to the most recent guidelines 1, C-peptide testing is an essential tool for assessing pancreatic beta cell function in diabetes management, and it should be used to guide treatment decisions and monitor disease progression.
From the Research
Enzymes Used to Check for Diabetes
- C-peptide (Connecting Peptide) is co-secreted with insulin and is used to assess functional β-cell mass 2
- C-peptide levels can be measured using various assays, including enzyme-linked immunosorbent assay (ELISA) and immunoradiometric assay (IRMA) 3
C-Peptide Measurement
- C-peptide measurement can be helpful in clinical practice to differentiate between type 1 and type 2 diabetes 4, 5
- C-peptide levels can be used to identify individuals at risk for or with type 1 diabetes with residual β-cell function 2
- C-peptide measurement can also be used to distinguish type 2 diabetes from Latent Autoimmune Diabetes in Adults and late-onset type 1 diabetes 2, 4
Assays Used for C-Peptide Measurement
- Ultrasensitive Mercodia enzyme-linked immunosorbent C-peptide assay (ELISA) 3
- Beckman immunoradiometric assay (IRMA) for C-peptide 3
- Time-resolved fluoroimmunoassay 6
- High-sensitivity commercial ELISA assay 2
Clinical Utility of C-Peptide Measurement
- C-peptide measurement can be used to assess endogenous insulin secretion in patients with diabetes 4, 5
- C-peptide levels can be used to predict clinical partial remission during the first year of type 1 diabetes 4
- C-peptide measurement can be used to assist in patient selection for islet cell transplantation and post-transplant monitoring 4