A rapid and precise LC-MS/MS for 25OHD measurements with the efficiency to separate 3-epi 25OHD3 was developed.
The performance of the newly built method was excellent and would be suitable for using in clinical laboratory.
3-epi 25OHD3 had little effects on routinely used NEPI-LC-MS/MS that could not separate 3-epi 25OHD3 from 25OHD3.
3-epi 25OHD3 status was firstly evaluated in China.