Plasma lead levels in normal and lead-intoxicated children.

Lead reaches tissues through the plasma, where the concentration of this ion is characteristically low. Little information exists on the mechanisms which determine the dynamics of lead in plasma. Measurement of plasma lead levels have been determined in normal and lead-intoxicated children, newborn infants, and children with sickle-cell disease. The results in all groups were remarkably similar and constant over a wide range of blood lead concentration and regardless of hematocrit. These results lend further support to the postulate that the red cell represents a repository for lead, maintaining plasma lead concentration within closely defined limits, and that methods other than an isolated measurement of plasma lead will be necessary to uncover a presumably dynamic transport system between red cell and plasma.