The PGA2 Quant-PAK has been designed for the convenient, precise quantification of PGA2 by GC- or LC-MS. It includes a 50 μg vial of PGA2-d4 and a precisely weighed vial of unlabeled PGA2, with the precise weight indicated on the vial. This unlabeled PGA2 can be used to quantify the PGA2-d4 standard by constructing a standard curve of peak intensity ratios (deuterated versus unlabeled).