Effect of transfusion on hemoglobin variants in preterm infants

To determine the effect of transfusion on hemoglobin (Hb) variants in very low birth weight infants and to correlate these changes with parameters measured in routine complete blood counts.

Hb variants were measured by capillary isoelectric focusing on 126 specimens from 25 very low birth weight infants during their hospital course. These results were compared with transfusion frequency, mean corpuscular volume (MCV), and red cell distribution width.

Mean initial Hb F level before transfusion was 87.1 +/- 5.1%, and a single 15 ml/kg packed red blood cell transfusion decreased the mean Hb F level to 54.0 +/- 4.7%. With frequent transfusions in the first month of life, there was progressive decline in Hb F content such that Hb F made up < 15% of the total Hb after five transfusions. There was a linear correlation between Hb F content and MCV, with a correlation coefficient (r) of 0.77 and a p value of < 0.0001. In most instances, when the MCV fell below 100 fl, the Hb F content was < 50%; when the MCV fell below 95 fl, the Hb F content was < 25%. There was a nonlinear correlation between Hb F content and red cell distribution width.

Transfusion in very low birth weight infants results in a rapid transition from Hb F to Hb A predominance. This transition is marked by a reduction in MCV that allows for prediction of the Hb F content.