Surrogate analyte approach for quantitation of endogenous NAD(+) in human acidified blood samples using liquid chromatography coupled with electrospray ionization tandem mass spectrometry.

•An LC–MS/MS assay for the quantitative determination of NAD+ in human whole blood using a surrogate analyte approach was developed and validated.•Parallelism was established between the surrogate analyte and the authentic analyte in the concentration range of 1.69–25μg/mL.•This validated assay was successfully applied to determine the baseline level of endogenous NAD+ in human blood from healthy volunteers.