§ Demographic variables: age, sex, race. § Personal history: group incompatibility, birth weight, gestational age, Apgar score at birth. § Medical history variables: feeding (breast, formula, breast and formula). § Physical examination variables: weight, presence or absence of cephalohematoma or broken clavicle. § Laboratory variables: transcutaneous bilirubin levels and serum bilirubin. § Income: yes/no § Length of stay in emergency department. |