New Ways of Measuring a Vitamin D

Funding support by HBMRF contributed to the research reported in the following paper.

Quantitation of 25-hydroxyvitamin D in dried blood spots by 2D LC-MS/MS without derivatization and correlation with serum in adult and pediatric studies

Jensen BP, Saraf R, Ma J, Berry S, Grant CC, Carmargo, CA, Sies CW.

Clinica Chemica Acta 481 (2018) 61-68

Measurement of Vitamin D status can assist with medical diagnosis. The metabolite 25-hydroxyvitamin D (250HD) is a reliable indicator of Vitamin D concentration and can be measured by immunoassay or by using liquid chromatography tandem mass spectroscopy (LC-MS/MS) of serum. Collection of dried blood spots (DBS) is less invasive, they are more easily transported and can be stored for longer so provide greater flexibility than fresh blood samples. But the volume of DBS sample available for analysis is limited so sensitive methodology is required.

Injection of a higher volume sample from DBS combined with online sample clean up increased the sensitivity of analysis so a complex derivatization step could be eliminated (saving time and consumable costs) without compromising the analytical result. The researchers were able to demonstrate that assessment of Vitamin D in DBS using LC-MS/MS was well correlated to that in fresh samples for adults. Further work is required to determine whether it can reliably be used in neonatal DBS