Phototherapy-Related Transient Direct Hyperbilirubinemia

Objective: We aimed to investigate the frequency and possible risk factors of phototherapy-related direct hyperbilirubinemia. Material and Methods: We scanned the medical records of 1301 patients who were admitted to the neonatology unit for indirect hyperbilirubinemia between 2005 and 2013. Infants with a clinical condition other than hyperbilirubinemia were excluded. Results: Following phototherapy both the direct bilirubin level and direct bilirubin/total bilirubin ratio increased (p<0.001 and p<0.001, respectively). The frequency of phototherapy-related direct hyperbilirubinemia was found to be 0.9% if the direct bilirubin/total bilirubin cut-off level was set to 20%. The elevated direct bilirubin level and direct bilirubin/total bilirubin ratio returned to normal within three days, although they were still significantly higher than the pre-phototherapy levels (p < 0.001; p < 0.001, respectively). The increase in direct bilirubin level and direct bilirubin/total bilirubin ratio were found to be brisker in patients with ABO incompatibility (p < 0.001 and p < 0.001, respectively). Conclusion: The direct bilirubin level and direct bilirubin/total bilirubin ratio may temporarily rise following phototherapy. This deviation is short term, and ABO incompatibility is the only identified risk factor.To prevent unnecessary investigations this phenomenon should kept in mind by the physicians caring for infants.