title: Haemolysis affects insulin but not C-peptide immunoassay.
abstract: Venous blood was taken at the end of a glucose infusion test in 19 individuals and divided into four aliquots, 3 of which were variably haemolysed by repeated passage through a 23-gauge needle to simulate traumatic venepuncture. Plasma insulin (measured by both a charcoal separation and a double-antibody method), C-peptide, and haemoglobin were measured in each aliquot, and haemolysis was also assessed visibly. A significant loss of immuno-assayable plasma insulin was found in samples with only a trace of visible haemolysis, with up to 90% lost in severely haemolysed samples. Plasma C-peptide was unaffected by haemolysis. This represents an additional advantage for the use of plasma C-peptide in assessing insulin secretion.
authors.affiliation: Diabetes Research Laboratories, John Radcliffe Hospital, Oxford, UK.
authors.forename: S
authors.initials: S
authors.lastname: O'Rahilly
authors.forename: M A
authors.initials: MA
authors.lastname: Burnett
authors.forename: R F
authors.initials: RF
authors.lastname: Smith
authors.forename: J H
authors.initials: JH
authors.lastname: Darley
authors.forename: R C
authors.initials: RC
authors.lastname: Turner
mesh_terms: D002096:C-Peptide / Q000097:blood*; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000235:genetics; D003951:Diagnostic Errors; D006454:Hemoglobins / Q000032:analysis; D006461:Hemolysis; D006801:Humans; D007328:Insulin / Q000097:blood*; D011863:Radioimmunoassay / Q000379:methods
chemical_list: D002096:C-Peptide; D006454:Hemoglobins; D007328:Insulin