The wearable artificial kidney created by Kolff and Jacobsen

In this history article, I describe my experience with the wearable artificial kidney (WAK) project of Dr. Willem Kolff in 1975. The WAK was unique and functioned well though it had an incomplete sorbent system. The company that licensed it redesigned it to become a more traditional dialysis system, suited for in‐center dialysis but without portability. At the end of this manuscript, I explain mistakes made in the steps to commercialization of the WAK, and lessons I learned from the experience.