Review Question - QID 109103

A 6-hour-old newborn boy is noted to have a “lump on his head” by his mother. She denies that the lump was present at birth and is concerned about an infection. The child was born at 39 weeks gestation to a 34-year-old G2P2 mother by vacuum-assisted vaginal delivery after prolonged labor. His birth weight was 3.8 kg (8.4 lb) and his length and head circumference are at the 40th and 60th percentiles, respectively. The mother was diagnosed during this pregnancy with gestational diabetes mellitus and received prenatal care throughout. All prenatal screening was normal and the 20-week anatomy ultrasound was unremarkable. His temperature is 98.6°F (37°C), blood pressure is 65/42 mmHg, pulse is 131/min, and respirations are 36/min. On physical exam, the child is in no acute distress. He has a 3x3 cm fluctuant swelling over the right parietal bone that does not cross the midline. There is no discoloration of the overlying scalp. Laboratory testing is performed and reveals the following:

Total bilirubin: 5.5 mg/dL
Direct bilirubin: 0.7 mg/dL

Which of the following is the most appropriate next step in management?