Certified reference material of testosterone-2,3,4-13C3 in 10 μg/mL acetonitrile, as part of the Testosterone Calibrator Kit CE marked for in vitro diagnostic (IVD) applications by mass spectrometry. Individual levels of testosterone in stripped serum are offered separately at concentrations ranging from 2 to 2,000 ng/dL. Each individual level is ready to use as a calibrator in LC-MS/MS testosterone methods. Separate options for a serum blank or the whole kit including calibrators, blank and Testosterone-2,3,4-13C3 in 10 μg/mL Acetonitrile are also available.