Accuracy of transcutaneous bilirubinometry compare to total serum bilirubin measurement.

BACKGROUND: Neonatal hyperbilirubinemia leads to bilirubin neurotoxicity. Noninvasive transcutaneous bilirubin (TcB) levels can be used as a screening tool for total serum bilirubin (TSB) levels.

OBJECTIVE: To evaluate the correlation of TcB for TSB levels before, during and after phototherapy and find the most reliable cutoff values of TcB levels with the highest sensitivity and specificity for TSB levels.

DESIGN: Diagnostic study.

MATERIAL AND METHOD: In this research, forehead TcB measurement was measured by the transcutaneous bilirubinometer (Minolta Airshilds Jaundice Meter, JM 103). The 224 paired TcB-TSB specimens from 74 term and nearterm newborns were study from September 2007 to October 2008. The mean postnatal age at the time of measurement was 57.85 +/- 22.15 hours. The mean gestational age was 38 +/- 1.29 weeks and mean body weight was 2,864.65 +/- 262 g.

RESULTS: The TcB and TSB values had linear correlation with significant correlation coefficient (r 0.81, p < 0.001). The correlation equation was TSB = 0.88 + 0.89 x TcB (r2 = 0.65). TcB levels tended be higher than TSB with mean difference of 0.44 mg/dL (95% CI: 0.7433-0.1323 mg/dL) and SD:1.64. TSB confirmation was recommended when TcB cutoff values greater than 9, 12, 13, 15 mg/dL at 24 (TSB:8 mg/dL), 36 (TSB: 10 mg/dL), 48 (TSB: 12 mg/dL) and 72 (TSB: 15 mg/dL) hours' postnatalage, respectively.

CONCLUSION: The TcB levels can accurately predict TSB with the different cutoff points at various postnatal ages before phototherapy.