Diagnostic Accuracy of Transcutaneous Bilirubinometry Versus Serum Bilirubin Level

Abstract

Objective: To assess the diagnostic accuracy of transcutaneous bilirubinometry over serum bilirubin level in newborns with hyperbilirubinemia.

Methodology: This cross-sectional study was conducted at Department of Neonatology, Children Hospital, PIMS Islamabad for six months from 01-09-20 to 28-02-21, included 150 jaundiced neonates of any gender over six months. Exclusion criteria included pre-treated hyperbilirubinemia, very premature or low birth weight infants, congenital abnormalities, or infants of jaundiced mothers. Post ethical clearance and parental consent, neonates were evaluated using the MBJ-20 transcutaneous bilirubinometer, with results compared to serum bilirubin levels. The study identified true and false diagnostic outcomes based on a ?12 mg/dL bilirubin threshold, signifying phototherapy initiation. Data analysis was performed with SPSS 26.0, calculating sensitivity, specificity, and accuracy, and determining diagnostic congruence through Pearson’s correlation and ROC AUC, with a significance threshold at p<0.05.

Results: The mean serum bilirubin level and transcutaneous bilirubin levels were 14.28 ± 2.21 mg/dL and 14.52 ± 2.72 mg/dL respectively, with a mean difference of 0.24± 1.38 mg/dL (t(149) = 2.141, p = .034). This difference demonstrating a statistically significant overestimation compared to serum bilirubin levels. The correlation between transcutaneous and serum bilirubin levels was strong (r = 0.864, p < 0.0001). For the 12 mg/dL phototherapy threshold, the transcutaneous method showed high sensitivity (95.59%) and specificity (78.57%), with an overall test accuracy of 94%. The Area Under the Curve (AUC) for the receiver operating characteristic was 0.962, indicating high diagnostic precision.

Conclusion: Transcutaneous bilirubinometry is a low-cost, noninvasive, and accurate screening test for hyperbilirubinemia with a high sensitivity specificity and positive predictive value (PPV).