Dr. Koa is a board-certified pathologist, specializing in renal pathology. He is a graduate of the University of the East Ramon Magsaysay
Memorial Medical Center. He completed his residency training in pathology at the University of the Philippines-Philippine General Hospital. He then completed fellowships at the Singapore General Hospital, Emory University School of Medicine in Atlanta, Georgia, and the University of North Carolina at Chapel Hill, USA. He is a former president of the Philippine Society of Pathologists.
