IMx (Abbott) Immunoassay of Insulin: A Practical Alternative to RIA Hyperinsulinemia Identification in Idiopathic Neurootology and Other Hyperinsulin Metabolic Disorders.
Hyperinsulinemia identification as defined by glucose/insulin tolerance has been established as the prime etiological factor in idiopathic neurootological disorders. Insulin assays by radioimmunoassay (RIA) and the IMx (Abbott) immunoassay yielded in 558 of 595 glucose/insulin tolerance a concurrence of 93.7%. The latter measures insulin without cross-reaction with proinsulin. The RIA methodology includes proinsulin. The IMx (Abbott), a micro-particle enzyme immunoassay (MEIA), gave lower values due to its nondetection of proinsulin. Based upon defined insulin values, the dynamic patterns of euinsulinemia, hyperinsulinemia with elevated fasting insulin levels and hyperinsulinemia with impaired and/or hyperglycemia glucose tolerance were concurred 100% by MEIA. All of the nonconcurrences were with normal glucose tolerances when the second and/or third hour insulin values were borderline. The limited utilization of RIA technology and the potential availability of enzymatic immunoassay which requires less technical skills presents MEIA as a practical and precise alternative to RIA hyperinsulinemia identification. The increasing world-wide significance of the clinical pathology of hyperinsulinemia becoming manifest in all disciplines of medicine, warrants the identification and/or exclusion of hyperinsulinemia by cost-effective technology.
Kraft
JR
Department of Clinical Pathology and Nuclear Medicine, Saint Joseph Hospital and Health Care Center, Chicago, IL 60657, U.S.A.