
EPP arises from reduced ferrochelatase activity and excess protoporphyrin made largely in the bone marrow. Accurate diagnosis depends on choosing the right specimen and the right laboratory, a step commercial assays often get wrong.

EPP arises from reduced ferrochelatase activity and excess protoporphyrin made largely in the bone marrow. Accurate diagnosis depends on choosing the right specimen and the right laboratory, a step commercial assays often get wrong.