FOR RESEARCH USE ONLY. NOT FOR USE IN DIAGNOSTIC PROCEDURES.
An enzyme immunoassay for the quantitation of intact proinsulin in human serum and plasma.
|Sample Type:||Serum, EDTA/Heparin Plasma|
|Analyte||Intact human proinsulin|
|Specimen||Serum, EDTA/Heparin Plasma|
|Specimen Volume||50 µL|
|Limit of Detection||0.3 pmol/L|
|Assay Range||~ 3-100 pmol/L|
|Precision CVs within-run||1.8-2.2%|
|Precision CVs between-run||1.7-4.0%|
|Incubation Time||2.5 hours|
|Cross-reactivity||- no cross reactivity has been observed|
- human insulin < 10,000 pmol/L
- human C-Peptide 50,000 pmol/L
- Des(31,32)-Proinsulin < 200 pmol/L
- Split(32,33)-Proinsulin 5,000 pmol/L
- Des(64,65)-Proinsulin* 200 pmol/L
- Split(65,66)-Proinsulin 1,000 pmol/L
Proinsulin is produced in the pancreatic ß-cells and is normally further processed to insulin and C-peptide. It is only seen in low concentrations in the plasma of healthy subjects. An increase in the insulin demand, as provided by insulin resistance in later stages of type 2 diabetes mellitus, can result in increased expression of proinsulin into the blood. Intact proinsulin is rapidly degraded, but is considered to be an independent cardiovascular risk factor. The intact molecule and its degradation products are known to block fibrinolysis because of plasminogen-activator inhibitor (PAI-1) stimulation. In clinical practice, fasting morning intact proinsulin can be used as highly specific indicator of clinically relevant insulin resistance, to serve as the basis for the selection of an insulin resistance therapy, and to monitor the therapeutic effect on ß-cell dysfunction. Patients with type 2 diabetes mellitus and with elevated fasting intact proinsulin levels should be regarded and treated as insulin resistant, in order to reduce the risk for further cardiovascular damage. Elevated fasting intact proinsulin levels may also be seen in patients with insulinoma, a benign insulin producing tumor of the pancreas.