Effect of transfusion and phlebotomy on serum ferritin levels in low birth weight infants.

The objective of this study was to determine the degree to which the balance of red blood cells between transfusions and phlebotomies affects iron stores, represented by serum ferritin levels, in low birth weight infants. A retrospective review was made of transfusions, phlebotomies, and ferritin level before initiation of oral iron administration in 29 low birth weight infants with a mean birth weight of 1001 +/- 304 gm (+/- 1 SD) and gestational age of 27.0 +/- 1.8 weeks. Correlation was determined between ferritin level and net balance of red blood cells, maturity, or age. Serum ferritin levels correlated with estimated net red blood cells gained or lost (r = 0.87, p < 0.0001, 95% confidence intervals 0.74 to 0.94). Serum ferritin level can be a useful guide to estimating iron stores in low birth weight infants who have undergone transfusion and phlebotomy. How serum ferritin level could be used to guide initiation of oral iron supplementation needs further study.