Comparing Kramer's rule with transcutaneous bilirubin vs. Kramer's rule only in reducing total serum bilirubin sampling among neonates with jaundice.

Background: In the Malaysian primary healthcare setting, neonatal jaundice (NNJ) screening uses either Kramer's Rule (KR), a visual assessment, or a combination with non-invasive transcutaneous bilirubin (TcB). However, data on the quantification of the need for total serum bilirubin (TSB) sampling between these approaches are limited. This study aimed to compare the frequency of blood draws required between the two cohorts, alongside investigating disparities in phototherapy initiation and severe hyperbilirubinemia occurrences.

Methods: This multicentre retrospective cohort study enrolled neonates from six primary healthcare clinics, with three using KR plus TcB and three using KR only for NNJ screening. Neonates with a gestational age of ≥ 35 weeks and without prior phototherapy or exchange transfusion for hyperbilirubinemia were included in the study until reaching either day 10 of life or hospitalization for any reason, defining the study endpoint. The minimum sample size required was 379 neonates in each cohort. Generalized Poisson regression was used to compare the number of blood draws required for TSB sampling between the two cohorts.

Results: Of 765 neonates included, the cohort using KR alongside TcB showed a 74% reduction in blood draw risk compared to KR alone cohort (IRR 0.26, 95% CI 0.23-0.39). There were no significant differences between cohorts in phototherapy initiation (25.5% vs. 24.4%), severe hyperbilirubinemia occurrence (0.0% vs. 0.0%) or rapid bilirubin level rise (0.3% vs. 0.8%).

Conclusion: Incorporating TcB alongside KR for NNJ screening significantly reduces the need for TSB sampling without causing an escalation in phototherapy initiation or severe hyperbilirubinemia occurrences, suggesting the potential to optimize NNJ management in the local primary care setting.