How to distinguish between physiological jaundice and pathological jaundice

Patient's question:

Baby's face is yellow just after birth

Doctor's answer:

Different onset times. Approximately 80% of full-term infants develop physiological jaundice 2-3 days after birth, while pathological jaundice usually appears earlier, often within 24-36 hours postpartum, and in preterm infants within 72 hours.
Different symptoms. Physiological jaundice is usually mild, with the child's skin appearing slightly yellow, first appearing on the face, torso, and limbs, and the sclera (whites of the eyes) remaining mostly normal. The baby is generally in good spirits, able to eat and sleep well. In contrast, children with pathological jaundice may have yellow faces, torsos, limbs, palms, and soles, with yellow sclera and yellow urine. They may also exhibit poor spirits, lethargy, fever, reduced appetite, vomiting, abdominal distension, edema, ascites, hepatosplenomegaly, anemia, and other symptoms. The accompanying symptoms vary depending on the underlying cause.
Different duration. Physiological jaundice is most pronounced around the 5th day after birth and gradually disappears within 7-10 days. Most preterm infants may develop jaundice, with the duration lasting about 2-3 weeks. Pathological jaundice, however, lasts longer—full-term infants show no signs of improvement after 2 weeks, and preterm infants after 3 weeks; alternatively, if jaundice disappears and then reappears, it should be closely monitored.
Different bilirubin levels. In physiological jaundice, the serum bilirubin level in full-term infants does not exceed 205 μmol/L, and in preterm infants, it does not exceed 256.5 μmol/L. In pathological jaundice, the serum bilirubin level exceeds the normal range: greater than 205.2 μmol/L in full-term infants and greater than 256.5 μmol/L in preterm infants.