Skip to main content
U.S. flag

An official website of the United States government

Dot gov

Official websites use .gov
A .gov website belongs to an official government organization in the United States.


Secure .gov websites use HTTPS
A lock ( ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

Shedding [Sun] Light on Vitamin D Metabolites

NIST SRM 2971 24R,25-Dihydroxyvitamin D3 Calibration Solution


SRM 2971

What: Ethanolic solution certified for the mass fraction value of 24R,25‑Dihydroxyvitamin D3 [24R,25(OH)2D3].

Why:  The vitamin D metabolite 25-hydroxyvitamin D (25OHD) is the serum biomarker measured to determine a person’s “vitamin D status.” This metabolite is further metabolized in the body, to both active and nonactive forms, such as 24R,25(OH)2D3, and the levels of these compounds in patient samples have shown promise towards the indication of kidney disease and hypercalcemic diseases.

Who: Clinical researchers working towards the development of techniques for the determination of 24,25(OH)2D3 in serum.

How:  This SRM is intended for the calibration of LC-MS and LC-MS/MS methods used for the determination of 24R,25(OH)2D3.   

Released November 6, 2018, Updated January 9, 2020