Classification of neonatal jaundice: I. Physiological jaundice: 1. Generally good; 2. Jaundice appears 2-3 days after birth in full-term infants, peaking at 4-5 days and subsiding at 5-7 days, with a maximum delay of 2 weeks; jaundice in preterm infants mostly appears 3-5 days after birth, peaking at 5-7 days and subsiding at 7-9 days, with a maximum delay of 3-4 weeks; 3. Daily bilirubin elevation <85μmol/L (5mg/dL) (dL); physiological jaundice threshold: 221μmol/L (12.9mg/dL) in term infants, <257μmol/L (15mg/dL) in preterm infants. Second, pathological jaundice: 1, jaundice within 24 hours after birth; 2, serum bilirubin > 221 μmol/L (12.9mg/dL) in term infants, > 257 μmol/L (15mg/dL) in preterm infants, or a daily rise of > 85 μmol/L (5mg/dL); 3, long duration of jaundice: > 2 weeks in term infants, > 4 weeks in preterm infants; 4, long duration of jaundice: > 2 weeks in term infants, > 4 weeks in preterm infants. 4. Jaundice recedes and recurs; 5. Serum conjugated bilirubin > 34 μmol/L (2 mg/dL). Any one of the above can be diagnosed as pathological jaundice.