Development and clinical application of a bioluminescence enzyme immunoassay for oxytocin.

The development of a highly sensitive analytical method for oxytocin could be useful in the diagnosis and treatment of autistic spectrum disorder. We previously developed a colorimetric enzyme immunoassay (EIA) for plasma oxytocin measurement. In this study, we developed a method to measure oxytocin concentrations using a higher sensitivity bioluminescent EIA. Biotinylated oxytocin bridged with five lysine residues was used in a competitive format. The standard curve range for oxytocin was 1.0 to 1000 pg/assay. In addition, there was good correlation between the colorimetric and bioluminescent immunoassays in terms of measured oxytocin concentration (r = 0.9665, n = 48). The bioluminescent EIA for plasma oxytocin was more rapid and provided higher sensitivity than the colorimetric immunoassay, making it suitable for clinical application.