Abstract
Erythrocyte coproporphyrin and protoporphyrin levels were detd. in normal newborn infants and older children. There is a significant elevation of erythrocyte protoporphyrin in children as compared with normal adults. This increase probably reflects the general Fe deficient state in children. There is a significant elevation of erythrocyte coproporphyrin in newborn infants as compared with normal adults. This increase probably reflects increased erythropoiesis in utero and rapidly disappears on the 4th and 5th day of life. The erythrocyte protoporphyrin and coproporphyrin should be regarded as abnormal if they exceed twice the standard deviation above the mean.