Haemolysis affects insulin but not C-peptide immunoassay.
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.
O'Rahilly
S
S
Diabetes Research Laboratories, John Radcliffe Hospital, Oxford, UK.
Burnett
M A
MA
Smith
R F
RF
Darley
J H
JH
Turner
R C
RC
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
D002096:C-Peptide; D006454:Hemoglobins; D007328:Insulin