Radioimmunoassay may overestimate insulin in non-insulin-dependent diabetics.
We have compared insulin concentrations measured by radioimmunoassay (RIA) in plasma from 50 fasting non-insulin-dependent diabetics (NIDDM) with those measured by a new monoclonal antibody-based two-site immunoradiometric assay (IRMA) of insulin (which has no significant cross-reaction with proinsulin-like molecules). We find that the RIA measures the sum of the insulin and proinsulin like molecules and that the IRMA insulin concentrations are 38% of those measured by the RIA in those diabetic subjects. We conclude that the importance of insulin deficiency in NIDDM may have been obscured by this error.
Temple
R C
RC
Department of Clinical Biochemistry, Addenbrooke's Hospital, Cambridge, UK.
Clark
P M
PM
Nagi
D K
DK
Schneider
A E
AE
Yudkin
J S
JS
Hales
C N
CN
D000328:Adult; D000368:Aged; D001786:Blood Glucose / Q000032:analysis; D003429:Cross Reactions; D003920:Diabetes Mellitus / Q000097:blood; D003924:Diabetes Mellitus, Type 2 / Q000097:blood*; D005260:Female; D006801:Humans; D015592:Immunoradiometric Assay; D007328:Insulin / Q000097:blood* / Q000276:immunology; D008297:Male; D008875:Middle Aged; D009765:Obesity; D011384:Proinsulin / Q000097:blood; D011863:Radioimmunoassay
D001786:Blood Glucose; D007328:Insulin; D011384:Proinsulin