Most neonatal jaundice is a physiological phenomenon, but if jaundice persists beyond 2 weeks of age in term infants or beyond 3 weeks of age in preterm infants, or if jaundice recedes and reappears, it is an abnormal sign and requires attention. For jaundice, the first distinction should be made between jaundice with elevated conjugated bilirubin and jaundice with elevated non-conjugated bilirubin. Jaundice with elevated conjugated bilirubin is basically a pathological condition and requires prompt medical attention. The diagnostic clues are a deepening of the urine color, which is yellow (normal neonatal urine is mostly colorless); a lightening of the stool color; and an elevation of direct bilirubin in the blood tests. For more information on why this type of jaundice must be seen promptly, see my article “What to know about cholestatic jaundice in infants”. Non-conjugated bilirubin jaundice may have a history of hemolysis, hematoma, etc. The urine is colorless and the direct bilirubin in the blood test is less than 20% of the total bilirubin. Please refer to my article “Non-conjugated bilirubin elevated jaundice” for reasons.