8-iso-15-keto PGE2 is an isoprostane, one member of a large family of biomarkers produced by the free radical peroxidative degradation of membrane lipids. 8-iso-15-keto PGE2 is the theoretical first metabolite of 8-iso PGE2 via the 15-hydroxy PGDH pathway. While a number of potent biological activities have been attributed to 8-iso PGE2, there are no published reports at this time regarding its metabolism.