This standard is intended for use in evaluating analytical methods for the determination of selected polychlorinated biphenyl (PCB) congeners, chlorinated pesticides and total cholesterol in human serum and

similar matrices. Reference values are also provided for selected polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). All of the constituents for which certified and reference values are

provided are naturally present in the freeze-dried human serum. A unit consists of five bottles of freeze-dried human serum.