Correlation between Transcutaneous Bilirubinemia and Blood Bilirubinemia in Screening Term Newborn for Neonatal Jaundice at the Essos Hospital Centre (EHC), Yaoundé, Cameroon

Abstract

Background: Early and non-invasive diagnosis of neonatal hyperbilirubinemia remains critical in dark skinned babies of low resource settings. Objective: To assess correlation/agreement between transcutaneous bilirubin (Tcb) and serum bilirubin (Tsb) values in full term neonates with jaundice. Methodology: An analytical cross-sectional study was conducted at the neonatology unit of the Essos Hospital Centre (EHC) from January to June 2019. All full-term neonates aged 0 to 7 days with suspected jaundice who did not receive phototherapy were eligible for the study. The enrolled neonates in the study were assessed clinically, then with the MBJ20 transcutaneous bilirubinometer (TcB). The MBJ20 transcutaneous bilirubinometer highest measurement over the forehead and the sternum were compared to TsB. Data were entered and then analysed with the CsPro7.2 and R (version 3.6.0) software. Correlation was captured by Bland & Alman plots and Concordance Correlation Coefficient (CCC) estimates. The Pearson correlation coefficient and Student test for paired data were used for descriptions purposes, and the significance level was 5%. Results: We recruited 88 neonates. The sex ratio of the babies included was 1.25 favouring males. Median Post-natal age was 3 days with 62% aged 72 hours or more. The mean TcB corresponding to the maximum average between frontal and sternal measurement was 153 mg/dl ± 48 and the average Tsb was 123.80 mg/dl ± 50.48. A good linear correlation was found between TcB and total serum bilirubin level r = 0.86 [0.80; 0.91]. Positive correlation was noted between both (forehead and sternum) TcB measurements sites, namely r = 0.78 and r = 0.86. The Bland & Altman plot measured the bias at -29.68 mg/l (confidence interval at 95%, 21.14 - 80.50). The CCC estimate was 0.2 varying from -0.22 to 0.76 according to TcB measurement threshold and post-natal age. The ROC area under the curve value for a threshold Conclusion: A good linear correlation was found despite a poor agreement between TcB and Tsb. TcB method systematically overestimated the value of TsB.