The nurse knows that jaundice first becomes visible in a newborn when serum bilirubin reaches which level?
1) 1 to 3 mg/dL (17.1-51.3 µmol/L)
2) 2 to 4 mg/dL (34.2-68.4 µmol/L)
3) 5 to 7 mg/dL (85.5-119.7 µmol/L)
4) 8 to 10 mg/dL (136.8-171 µmol/L)