Novel electrochemiluminescence immunoassay exclusively for full-length parathyroid hormone during treatment with cinacalcet for secondary hyperparathyroidism.

A novel, electrochemiluminescence immunoassay that exclusively measures full-length parathyroid hormone (PTH), called Elecsys PTH (1-84) assay, is currently under development for clinical use. We measured serum PTH levels using this novel assay, as well as the Elecsys Intact PTH assay and the Whole PTH immunoradiometric assay, in 53 hemodialysis patients who participated in a 52-week clinical trial of cinacalcet. At baseline, serum PTH (1-84) levels measured with the Elecsys PTH (1-84) assay and those with the Whole PTH assay were comparable, and both values were significantly lower than Elecsys Intact PTH levels. After 52 weeks of cinacalcet treatment, Elecsys PTH (1-84) levels and Whole PTH levels decreased significantly by 56% and 60% from baseline, respectively. These results indicate that the Elecsys PTH (1-84) assay provides comparable data to the Whole PTH assay for monitoring parathyroid function in patients receiving hemodialysis. Introduction of this novel automated immunoassay would provide more widespread measurements of full-length PTH (1-84) in clinical practice.