C-peptide

The human C peptide is a linear chain consisting of 31 amino acids with a molecular weight of 3020. C-peptide and insulin are secreted from B cells into the blood in equal molecular weight. It is not taken up by liver cells, mainly in the kidney and is excreted from the kidneys. C peptide is not biologically active, does not bind to receptors on the cell membrane, and is not degraded, and its half-life is 3-4 times that of insulin. Basic Information Specialist classification: growth and development examination classification: blood examination Applicable gender: whether men and women apply fasting: not fasting Tips: When type 2 diabetes is not treated with insulin, C peptide is normal before and after meals. Normal value (1.0 ± 0.23) ng / ml, the peak after oral glucose was seen at 60 minutes, the concentration was 3.1 ng / ml. Clinical significance Fasting and postprandial C-peptide assays have great implications for the typing and early diagnosis of diabetes, the establishment and adjustment of treatment regimens, and the pathogenesis of diabetes. (1) Evaluation of islet β-cell secretory function Since insulin and C-peptide are secreted by islet β-cells in equal molar concentrations, little uptake in the liver, slow degradation in peripheral blood, and cross-immunization of C-peptide with insulin antibodies The reaction, so the C peptide value can more accurately reflect the reserve and secretion function of islet β cells. (2) Classification of Diabetes The fasting C-peptide level and C-peptide release experiments are important for the identification of type 1 and type 2. The level of C-peptide in the fasting and post-prandial phases of type 1 diabetes was lower, suggesting that the secretion function of islet β cells in type 1 diabetes patients is seriously deficient. The fasting C-peptide value of patients with type 2 diabetes is not low, even higher than normal, but the C-peptide value is lower than normal after the sugar load, and the peak appears after 2 hours, indicating that the insulin release function is poor, and the islet β-cell reserve function insufficient. (3) differential diagnosis of hypoglycemia, hypoglycemia caused by endogenous hyperinsulinemia caused by islet β-cell tumor, serum insulin and C-peptide values ​​are elevated; diabetes patients with hypoglycemia caused by excessive injection of exogenous insulin , its serum insulin value is elevated and the C peptide value is lower. Low results may be diseases: hypoglycemia results may be high. Diseases: Precautions for childhood diabetes Patients with type 1 diabetes had lower C peptides before and after meals. When type 2 diabetes is not treated with insulin, the C peptide is normal before and after eating. Inspection process Blood is drawn for testing. Not suitable for the crowd Those without examination indications should not be tested. Adverse reactions and risks 1. Infection: Pay attention to aseptic operation when collecting blood, avoid contamination of water and other parts at the blood collection site to avoid local infection. 2, bleeding: after the blood is given a full compression time, especially coagulopathy, bleeding tendency, to avoid local subcutaneous oozing, bruising and swelling.