The more there are eighty percent of newborns, the phenomenon of jaundice will occur, which is a common phenomenon in newborns. Generally, according to the physical condition of the newborn or the state of birth, the clinical manifestations of jaundice will be different, so the normal value of the judgment criteria are also different, as follows: First, the normal value of serum bilirubin concentration in the detection of jaundice in normal healthy newborns is no more than 12.9 mg/dl. However, this normal range is also a dynamic process, generally full-term infants appear bilirubin 3 to 4 days after birth, peaking at 5 to 6 days, and then gradually subsiding after 10 to 13 days. If the value of jaundice exceeds 6 mg/dl on the first day after birth or 9 mg/dl on the second day after birth, it is also pathological jaundice, so the peak change of jaundice is a dynamic process. Second, the physiological jaundice of preterm infants is generally more serious than that of term infants, so the serum bilirubin concentration will be higher, generally not more than 15mg/dl are normal, of course, the value of jaundice is also related to the age of the day, you can refer to the same gestational age preterm infants bilirubin curve to determine, and the duration will also be longer than that of term infants, generally not more than 1 month after birth. Finally, physiological jaundice is normal in newborns, but if the jaundice appears early, lasts for a long time, and is severe, with delayed remission or receding and reappearing, and if the direct bilirubin is elevated, it is likely to be pathological jaundice and requires prompt medical attention.