A nurse is assessing a newborn who is 12 hours old. The infant's total serum bilirubin is 13 mg/dL and jaundice is visible on the face and chest. The nurse knows this level is most likely dropdownhyperbilirubinemia and prepares the infant for dropdownwhile assessing for underlying causes such as hemolysis. infection, or metabolic disorders.

Pathologic jaundice (Select 1): The most critical factor here is that the jaundice appeared within the first 24 hours of life. Physiologic jaundice typically appears after 24 hours, peaks between days 3–5, and usually does not reach levels as high as 13 mg/dL so rapidly. A level of 13 mg/dL at only 12 hours old is significantly elevated and indicates a rapid rise, which is characteristic of pathologic conditions like Rh/ABO incompatibility or sepsis. Phototherapy (Select 2): This is the first-line medical intervention for significant hyperbilirubinemia. It uses light energy to change unconjugated bilirubin into a water-soluble form (lumirubin) that can be excreted in the bile and urine without needing to be processed by the liver.