Evaluation of the free erythrocyte porphyrin (FEP) test in a private practice: the incidence of iron deficiency and increased lead absorption in 9- to 13-month-old infants.

With the free erythrocyte prophyrin (FEP)/hematocrit ratio as a screening test, three of 122 9- to 13-month-old children had iron deficiency (FEP 147 to 286 microgram/100 ml of RBCs). The hematocrit alone could not identify these children. All three were drinking more than one quart of cow's milk per day. On follow-up examination of seven children with values of FEP of 100 to 140 microgram/100 ml of RBCs, two became anemic and one demonstrated increased lead absorption. Children with values of FEP below 100 microgram/100 ml of RBs (2 SD above the mean) did not develop anemia. Teaching parents to restrict cow's milk intake below one quart per day could be an effective means of preventing iron deficiency as identified by FEP screening. The child with increased lead absorption could not have been recognized by hematocrit alone.