Advances in the measurement of vitamin D binding protein.

Vitamin D binding protein (DBP) is a polymorphic protein known for its function in transporting vitamin D metabolites. DBP also plays several other important roles in the body's response to tissue damage and inflammation. Measurement of DBP is fundamental to understanding its relationship to vitamin D status and to elucidating potential links between DBP concentration and various health outcomes. Early studies on DBP primarily used antibody-based techniques for quantification, and mass spectrometry-based methods have been reported during the past decade. This review will outline the different methodologies used in DBP studies and to assign values to reference materials, describe their advantages and limitations, and highlight some future trends.