Jaundice is a condition caused by high levels of bilirubin in the blood. Bilirubin is produced from the breakdown of red blood cells and processed by the liver. Jaundice can be caused by issues before, within, or after the liver's processing of bilirubin. In newborns, jaundice is often caused by the immature liver's inability to effectively break down bilirubin from red blood cell breakdown. Jaundice is diagnosed through physical exams, blood tests, and imaging tests and treated based on the underlying cause.