Assessment of Copper Status in Preterm Infants

Preterm infants are particularly at risk of copper deficiency but there is no method for assessing copper status in preterm infants that has been unequivocally accepted. We explored the potential value of assays of erythrocyte copper concentration and erythrocyte superoxide dismutase (SOD) activity. Erythrocyte copper was measured by continuous nebulization flame atomic absorption spectrophotometry using a slotted tube atom trap. Erythrocyte SOD activity was measured by an automated method based on the inhibition of pyrogallol autoxidation. The methods gave reproducible results and the sample volumes were small. Due to the high frequency of blood transfusions, only 38% of the infants investigated had any results for erythrocyte copper or SOD that were considered to be unaffected by transfusion. Compared with adults, there appeared to be a difference in the distribution of copper in the erythrocytes of the small group of infants whose erythrocyte biochemistry was unaffected by blood transfusion. We conclude that neither erythrocyte copper nor erythrocyte SOD is likely to be of much value in assessing copper status in preterm infants.