Q75
Single choice
A 4-day-old infant presents with yellow discoloration of the skin and sclera. The baby was born at term by a normal vaginal delivery. Pregnancy was uncomplicated; there were no risk factors for sepsis and no history of maternal alcohol or drug use. The baby is breast-fed and has been nursing every 2 hours, about 10 minutes at each breast. The bilirubin level is 15 mg/dL (all unconjugated), the hematocrit is 45%, and the Coombs test is negative.
Which of the following is the most likely diagnosis?