RT Book, Section A1 Gomella, Tricia Lacy A1 Eyal, Fabien G. A1 Bany-Mohammed, Fayez SR Print(0) ID 1168356811 T1 Hyperbilirubinemia: Unconjugated, On Call T2 Gomella's Neonatology: Management, Procedures, On-Call Problems, Diseases, and Drugs, 8e YR 2020 FD 2020 PB McGraw-Hill Education PP New York, NY SN 9781259644818 LK accesspediatrics.mhmedical.com/content.aspx?aid=1168356811 RD 2024/03/28 AB An infant’s indirect (unconjugated) serum bilirubin level is elevated at 10 mg/dL. Unconjugated (indirect) bilirubin is the fraction of serum bilirubin that has not been conjugated with glucuronic acid in the liver. The exact definition of a physiologic range and management of indirect hyperbilirubinemia are complex and based on many factors, including gestational age (GA), postnatal age, birthweight, disease state, risk factors, ethnicity, and hydration and nutritional status. Total serum bilirubin (TSB) is the sum of direct (conjugated) and indirect (unconjugated) bilirubin. The indirect bilirubin is calculated by subtracting the direct bilirubin from the total bilirubin. Transcutaneous bilirubin (TcB) is a measurement of TSB from an instrument that uses reflectance measurements on the skin and correlates well with the laboratory TSB value. Unconjugated hyperbilirubinemia is usually transient and physiologic in the newborn period, but it is important to note that kernicterus (chronic bilirubin encephalopathy) is still occurring in the developed world.