While the role of vitamin D in bone metabolism is well established, little research has been performed to understand its role in other diseases. In today's clinical research laboratories, considerable time, effort, and funds are being applied to better define the link between vitamin D status and a variety of diseases – such as cancers, multiple sclerosis, heart disease, and diabetes.

Total 25OHD (that is, the sum of 25OHD₂ and 25OHD₃) has been a challenge to measure accurately because the antibodies used in some immunoassays do not have 100% co-specificity for both 25OHD₂ and 25OHD₃. Therefore, many clinical research laboratories have now adopted LC-MS/MS methods like the ACQUITY UPLC I-Class System and Xevo TQD Mass Spectrometer for measuring total 25OHD while also allowing independent quantification of 25OHD₂ and 25OHD₃.

For sample preparation, we also recommend Oasis PRiME HLB µElution plates. Oasis PRiME HLB sorbent is designed to simplify solid-phase extraction (SPE) by taking advantage of the desirable water-wettable and retention characteristics of Oasis HLB while providing cleaner samples in a streamlined workflow.