Evaluation of the cross-reactivity of 25-hydroxyvitamin D2 on seven commercial immunoassays on native samples.

Introduction: In serum, 25-hydroxy-vitamin D (25(OH)D) can be found in two forms, namely 25(OH)D2 and 25(OH)D3. We recently published a mathematical method to estimate the 25(OH)D2 recovery without spiking the samples. Since then, new “total” vitamin D immunoassays have appeared on the market (Roche “Total” vitamin D, Siemens Centaur vitamin D “total”, “total” vitamin D on DiaSorin Liaison XL, Abbott Architect Vitamin D). We aimed to study the 25(OH)D2 recovery of these new immunoassays and re-evaluate the cross-reactivity of previously studied assays (IDS iSYS Vitamin D and DiaSorin RIA).