Total 25-Hydroxyvitamin D Determination by an Entry Level Triple Quadrupole Instrument: Comparison between Two Commercial Kits
Typical SRM chromatograms of a serum sample (23.4 ng/mL 25-OHD3 and 25-OHD2 not detectable) assayed using the Chromsystems kit. The retention time of 25-OHD2/D3 is 2.8 minutes (a). Typical SRM chromatogram of a serum sample (21.8 ng/mL 25-OHD3 and 25-OHD2 1.6 ng/mL) assayed using the PerkinElmer kit. The retention time is 4.0 min (b).