Skin residual bilirubin volume (SRBV): a physiologically informed framework for transcutaneous bilirubin interpretation in neonates
File(s)
Published version
Author(s)
Amadi, Hippolite
Type
Journal Article
Abstract
Background: Transcutaneous bilirubinometry (TcB) is increasingly relied upon for neonatal jaundice management in settings without access to laboratory-based total serum bilirubin (TSB) testing. However, inconsistent agreement between transcutaneous bilirubin levels (TBL) and TSB limits its reliability as a standalone clinical tool.
Objective: To propose and evaluate skin residual bilirubin volume (SRBV) as a physiological explanation for TcB–TSB discordance and to assess its impact on TcB interpretation during diagnosis, treatment, and recovery.
Methods: This observational, multicentre study was conducted in resource-limited neonatal care settings. TcB readings were calibrated against laboratory TSB in non-jaundiced neonates (TSB <3 mg/dL). Neonates undergoing phototherapy were monitored using paired TcB measurements obtained immediately after treatment interruption (TBL-out) and prior to treatment resumption (TBL-return). TSB was measured before treatment, during treatment, and prior to discharge where feasible. Patterns of TcB–TSB disparity and the ‘Recovery Value Flip (RVP)’ phenomenon were analysed.
Results: TBL consistently equalled or exceeded TSB in cases with paired measurements. Early in treatment at higher bilirubin levels, TBL-return exceeded TBL-out, indicating persistent cutaneous bilirubin. A reproducible RVP was observed, after which TBL-return became lower than TBL-out, coinciding with sustained bilirubin decline. SRBV contribution varied with bilirubin level and treatment phase.
Conclusion: SRBV provides a biologically plausible explanation for TcB–TSB discordance and dynamic TcB behaviour. Incorporating SRBV into TcB interpretation enables physiologically informed monitoring, improving safety and reliability in laboratory-limited neonatal settings.
Objective: To propose and evaluate skin residual bilirubin volume (SRBV) as a physiological explanation for TcB–TSB discordance and to assess its impact on TcB interpretation during diagnosis, treatment, and recovery.
Methods: This observational, multicentre study was conducted in resource-limited neonatal care settings. TcB readings were calibrated against laboratory TSB in non-jaundiced neonates (TSB <3 mg/dL). Neonates undergoing phototherapy were monitored using paired TcB measurements obtained immediately after treatment interruption (TBL-out) and prior to treatment resumption (TBL-return). TSB was measured before treatment, during treatment, and prior to discharge where feasible. Patterns of TcB–TSB disparity and the ‘Recovery Value Flip (RVP)’ phenomenon were analysed.
Results: TBL consistently equalled or exceeded TSB in cases with paired measurements. Early in treatment at higher bilirubin levels, TBL-return exceeded TBL-out, indicating persistent cutaneous bilirubin. A reproducible RVP was observed, after which TBL-return became lower than TBL-out, coinciding with sustained bilirubin decline. SRBV contribution varied with bilirubin level and treatment phase.
Conclusion: SRBV provides a biologically plausible explanation for TcB–TSB discordance and dynamic TcB behaviour. Incorporating SRBV into TcB interpretation enables physiologically informed monitoring, improving safety and reliability in laboratory-limited neonatal settings.
Date Issued
2026-05-14
Date Acceptance
2026-04-30
Citation
Frontiers in Pediatrics, 2026, 14 (1)
ISSN
2296-2360
Publisher
Frontiers Media S.A.
Journal / Book Title
Frontiers in Pediatrics
Volume
14
Issue
1
Copyright Statement
© 2026 Amadi. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
License URL
Subjects
Jaundice, Neonatal
Phototherapy
Low-resource settings
Non-invasive monitoring
Recovery Value Flip (RVP)
Skin residual bilirubin volume (SRBV)
Transcutaneous bilirubinometry
Publication Status
Published
Article Number
1815793
Date Publish Online
2026-05-14