Vitamin D assays in clinical laboratory: Past, present and future challenges

Chemiluminescence immunoassays (CLIA), radioimmunoassy (RIA), and binding protein assay are belonging to the binding assay, while the chemical assay includes high performance liquid chromatography (HPLC) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). Significant differences in the 25(OH)D determination were observed between various assays. Standardization and harmonization of 25(OH)D measurements are therefore urgently needed. The widespread introduction of well standardized assays in clinical laboratories is the challenge in the next years.