Comparison of skin sites for estimating serum total bilirubin in in-patients and out-patients: chest is superior to brow.

OBJECTIVE: [corrected] To compare transcutaneous bilirubin readings from the chest and forehead of inpatient and outpatient infants to investigate whether one site is more accurate for estimating serum bilirubin concentration.
METHODS: In all, 31 infants were followed with serum and transcutaneous bilirubins using BiliChek trade mark at two skin sites.
RESULTS: For inpatients average chest bilirubin was 0.4 mg/dl (7 micromol/l) higher than serum while brow was 0.3 mg/dl (5 micromol/l) lower. For outpatients, skin readings from both sites underestimated serum values. Chest estimates were 0.6 mg/dl (10 micromol/l) lower; brow was 2.1 mg/dl (36 micromol/l) lower (p<0.0001). Correlation coefficients and mean differences between skin and serum values for Hispanic and non-Hispanic infants were similar.
CONCLUSIONS: In our inpatients, chest and brow readings approximated serum values. After discharge, brow readings were lower than serum values by almost 20%, while chest readings were underestimated by 5%. We recommend using the chest for transcutaneous bilirubin estimates.