Methodological aspects on C-peptide measurements

Acta Med Scand Suppl. 1983;671:53-9. doi: 10.1111/j.0954-6820.1983.tb08548.x.

Abstract

It is rather difficult to draw conclusions from reported C-peptide values, as the methods for determination differ, and C-peptide may be measured in serum or in urine with the patient fasting or after stimulation. We have followed prospectively 49 children with IDDM with regular determinations of serum C-peptide fasting and after a standardized breakfast. A subgroup of seven patients have been studied more thoroughly with 24-hour-profile of serum C-peptide, C-peptide excretion in urine, and stimulation by i.v. glucose + i.v. arginine. Our results indicate that the stimulation of the beta cells usually reaches a maximum around a blood glucose level of 10-12 mmol/l leading to a curve linear relationship between serum C-peptide and blood glucose. Thus a simple quotient is not so useful but the degree of stimulation should be stated and actual blood glucose value noticed. Stimulation with a standardized breakfast gives roughly the same information as maximal stimulation with i.v. glucose + arginine, and little extra information is found by a 24-hour-profile. Urinary C-peptide may give valuable information if it is related to the actual degree of metabolic balance. It can be of special interest in patients with very low serum C-peptide levels.

Publication types

  • Clinical Trial
  • Controlled Clinical Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Arginine
  • Blood Glucose / analysis
  • C-Peptide / blood*
  • C-Peptide / urine
  • Child
  • Child, Preschool
  • Diabetes Mellitus, Type 1 / blood*
  • Diabetes Mellitus, Type 1 / diagnosis
  • Diabetes Mellitus, Type 1 / urine
  • Eating
  • Female
  • Glucose
  • Humans
  • Male
  • Peptides / blood*

Substances

  • Blood Glucose
  • C-Peptide
  • Peptides
  • Arginine
  • Glucose