Cayman's PAF-AH Inhibitor Screening Assay uses 2-thio PAF as a substrate for PAF-AH. Upon hydrolysis of the acetyl thioester bond at the sn-2 position by PAF-AH, free thiols are detected using DTNB also known as Ellman's reagent. Cayman's PAF-AH Inhibitor Screening assay includes human plasma PAF-AH and is a time-saving tool for screening inhibitors.