An evaluation of automated methods for measurement of serum 25-hydroxyvitamin D

ObjectivesTo compare two new automated assays with the well-established reference method, DiaSorin radioimmunoassay (RIA), for quantitation of serum total 25-hydroxyvitamin D [25(OH)D].Methods25(OH)D from human sera (n = 158) was measured using DiaSorin RIA and two automated platforms, DiaSorin “LIAISON 25 OH Vitamin D TOTAL”, and Roche Modular “Vitamin D3 (25-OH)”. Methods were compared by regression and Bland–Altman analyses.ResultsDiaSorin LIAISON demonstrated a stronger correlation (r = 0.918) and better agreement (bias = − 0.88 nmol/L) with DiaSorin RIA than the Roche Modular assay (r = 0.871, bias = − 2.55 nmol/L). Precision ranges (CV%) for the RIA, LIAISON, and Roche Modular assays, respectively, were: within run (6.8–12.9%, 2.8–8.1%, and 1.9–5.5%), and total precision (7.4–14.5%, 7.3–17.5%, and 7.6–14.5%).ConclusionDiaSorin LIAISON displayed the best correlation and agreement with DiaSorin RIA. The DiaSorin LIAISON 25 OH Vitamin D TOTAL assay is an accurate and precise automated tool for serum total 25(OH)D determination.