SHIFT FROM FETAL TO ADULT HEMOGLOBIN PRODUCTION IN A PRETERM INFANT AFTER EXCHANGE-TRANSFUSION - A QUANTITATIVE APPROACH

To evaluate the quantitative aspects of the shift in production from f etal hemoglobin (HbF) to adult hemoglobin (HbA) the HbF and HbA mass w ere estimated in a preterm infant (gestational age 29 weeks)for 22 wee ks after an exchange transfusion the second day of life, leading to an initial HbA% of 100. Up until the estimated time of delivery, the HbA mass declined continuously, at a rate corresponding to a survival tim e of the transfused HbA erythrocytes of 100 days, and the rise in tota l hemoglobin mass could be ascribed solely to a rise in the HbF mass. HbF% maximum was reached 3 weeks before HbF mass maximum and, thus, th e HbF% and HbA% time courses gave no basis for evaluation of the produ ction/destruction balance of HbF and HbA erythrocytes. The applied qua ntitative approach seems to be a useful additional procedure for evalu ating the switch from HbF to HbA production and for estimating HbA ery throcyte survival time in preterm infants.