The iLite® Insulin Assay Ready Cells can be used to quantify insulin activity in human serum (without interference from factors present in human serum including IGF-1) and for quantification of the activity of neutralizing anti-Insulin antibodies. Insulin is a peptide hormone produced by beta cells in the pancreas to regulate the metabolism of carbohydrates and fats. Insulin is provided within the body in a constant proportion to remove excess glucose from the blood. When control of insulin levels fails, diabetes mellitus can result. As a consequence, insulin is used medically to treat some forms of diabetes mellitus. Insulin exerts its activity by binding to a high affinity heterodimeric receptor, CD220, which possesses intrinsic tyrosine kinase activity. Binding of insulin to the insulin receptor alpha chain, results in receptor dimerization, receptor auto-phosphorylation, and signaling via the IR beta chain. The insulin-like growth factor-1 (IGF-1) can also bind with low affinity to the IR and hence potentially interfere with an assay based on activation of the IR. Furthermore, the presence of insulin in serum samples could also interfere with the detection of neutralizing antibodies (NAbs). The iLite® Insulin Assay Ready Cells has been designed to eliminate interference from presence of insulin in serum samples, IGF-1 and IGF-2.