Whether jaundice up to 22mg/dl will enter the brain depends on whether it is a newborn or an adult. For newborns, serum total bilirubin up to 20mg/dl, and for low-birth-weight infants, serum total bilirubin up to 10-14mg/dl can cause bilirubin encephalopathy, whereas for adults, serum total bilirubin up to 22mg/dl will not cause bilirubin encephalopathy in general. The liver of newborns is immature, so it can’t combine indirect bilirubin with glucuronic acid and convert it into direct bilirubin, and indirect bilirubin is fat-soluble bilirubin, which can pass through the blood-brain barrier, therefore, indirect bilirubin is the main cause of bilirubin encephalopathy in newborns, and it can be caused by serum total bilirubin up to 20 mg/dl in newborns, and up to 10-14mg/dl in low-birthweight infants. Bilirubin encephalopathy. In addition, conditions such as hemolytic disease of the newborn can lead to neonatal bilirubin encephalopathy. For adults, serum total bilirubin of 22mg/dl generally does not cause bilirubin encephalopathy because the liver can well convert indirect bilirubin to direct bilirubin, and direct bilirubin cannot pass the blood-brain barrier.