Clinical Information

Insulin is a peptide hormone that plays a critical role in regulation of blood glucose levels; thus, prescribed insulin therapy is widely used for treatment of type 1 or type 2 diabetes mellitus. However, a large and increasing proportion of clinically used insulin preparations are no longer based on naturally occurring insulin but are instead insulin analogs created using recombinant DNA technology to modify human insulin to alter its pharmacokinetics and pharmacodynamics. This results in insulin analogs with rapid onset and offset of action, or conversely, delayed onset but a concomitant delay in the offset of insulin action. Current immunoassays for insulin have been designed to detect the native (natural) form of human insulin in serum or plasma. No currently available insulin immunoassays detect these insulin analogs with the same reliability as natural insulin, while the degree of detection cross-reactivity with insulin analogs varies between different insulin immunoassays. Thus, insulin analogs present unique challenges when assessing patients exhibiting hypo- or hyperglycemia. This novel liquid chromatography-high-resolution mass spectrometry test overcomes the limitations of currently available immunoassays by enabling simultaneous detection and quantitation of native human insulin and the insulin analogs aspart, glulisine, lispro, and glargine. These measurements are beneficial for monitoring treatment adherence of prescribed insulin therapy in patients with diabetes and unexpected hyperglycemia. This test is also useful in assessment of patients with unexplained hypoglycemia and it is uniquely suited to identify factitious hypoglycemia caused by the surreptitious use of insulin analogs or insulin.