The reliability of transcutaneous bilirubin measurements at different sites before and after phototherapy compared with total serum bilirubin in neonates / 中国新生儿科杂志

ABSTRACT

Objective To evaluate the accuracy of the transcutaneous bilirubin (TcB) at different sites including the chest (covered and uncovered),forehead and scapula,compared with total serum bilirubin (TSB) before and after phototherapy.Method Neonates who underwent blood test of TSB together with the average TcB at chest over 6 mg/dl from September 2015 to July 2016 in our Hospital were enrolled in our study.TcB measurements were done by the transcutaneous bilirubinometer (JH20-1 C) at the sites of the chest,forehead and scapula within 30 minutes after venous or arterious blood sampling for testing TSB after admission.An area of 2 cm diameter over the left chest was covered during phototherpy.TSB was tested immediately and within 12 ～ 24 hours after phototherapy,while TcB was measured within 0.5 hour after blood sampling at the covered sites over the left chest,right chest,forehead and scapula.IBM SPSS 20.0 software was used for data analysis.Data were compared via Pearson correlation analysis,ANOVA of repeated measurement data,student's t test and Bland-Altman analysis.Result A total of 437 data were collected from 364 neonates were enrolled in our study.Before phototherapy,the values of TcB at different sites were highly correlated and consistent with TSB (P ＜ 0.05),especially taken from the chest (the difference value of TcB and TSB-1.2 ± 2.3 mg/dl).Immediately and within 12 ～ 24 hours after the phototherapy,the values of TSB and TcB taken from the covered left chest showed the highest consistency (-1.2±2.3 mg/dl and-0.5 ± 1.6 mg/dl).When TSB exceeded 15 mg/dl before phototherapy,the difference between TSB and TcB taken from chest was 1.5 ± 1.6 mg/dl,while if TSB was below 15 mg/dl,the difference was-1.9 ± 1.9 mg/dl.They were significantly different (P ＜ 0.001).And difference between TSB and TcB taken from chest was not affected by gender gestational age,birth weight,days of birth and different measurements.When TcB taken from the covered or uncovered chest was less than the TSB threshold value of 3.3 mg/dl for phototherapyl,or the TcB of the left covered sternum lower than the threshold value of 2.6 mg/ml for cessation of phototherapy,97.5％ of the TSB would not exceed the corresponding value.Conclusion The TcB values of both uncovered chest before phototherapy and covered chest after phototherapy were highly consistent with TSB,and could be applied in the replacement of TSB in the assessment and management of neonatal jaundice.