Transient Abnormalities in Serum Bilirubin and Lactate Dehydrogenase Levels following Red Blood Cell Transfusions in Adults

Background: The effect of transfusion of small amounts of packed red blood cells (PRBC) on serum chemistry values is not known. Methods: We studied 73 adult patients without evidence of bleeding who received 2-unit PRBC transfusions. In study 1 (n = 39), we examined multiple laboratory values pretransfusion and 15 minutes, 1 hour, 2 hours, and 24 hours posttransfusion. In study 2 (n = 34), we examined changes in fractionated bilirubin, lactate dehydrogenase, and haptoglobin prior to and 1 hour following the transfusion. Results: Total bilirubin increased from a median pretransfusion baseline of 0.7 mg/dL to 1.4 mg/dL shortly after transfusion (P<0.0005), and then returned to normal 24 hours later. Of the 36 patients with normal pretreatment total bilirubin levels, 17 (47%) became transiently abnormal. The lactate dehydrogenase level increased similarly 15 minutes after transfusion, but returned to baseline 24 hours later. The unconjugated bilirubin level increased from a median baseline pretransfusion value of 0.3 mg/dL to 1.1 mg/dL at 1 hour posttransfusion (P<0.0005). No significant changes were noted in conjugated bilirubin levels or haptoglobin concentration following transfusion. Conclusions: Transient increases in serum bilirubin and lactate dehydrogenase are seen following transfusion of PRBC. These data should be considered when interpreting laboratory values during the first few hours after a transfusion.