1 Department of Pediatrics, Hospital of the University of Pennsylvania, 3400 Spruce St, Philadelphia, PA 19104
We appreciate the concerns raised by Carpentieri et al. Unfortunately, there is no reliable method currently available for determining the body's zinc status in routine clinical practice. Although erythrocyte and leukocyte zinc determination may be more reliable than plasma levels, it has been noted that erythrocyte zinc content rises progressively during the first 12 years of life and this may limit its applicability in children.1 Moreover, to our knowledge, there is no published study of leukocyte or erythrocyte zinc levels in premature infants of different gestational and postnatal ages.