Background & Aims: Hepatic steatosis (HS), particularly macrovesicular steatosis (MaS), influences transplant outcomes. Accurate assessment of MaS is crucial for graft selection. While traditional assessment methods have limitations, non-invasive spectroscopic techniques like Raman and reflectance spectroscopy offer promise. This study aimed to evaluate the efficacy of a portable ambient light-compatible spectroscopic system in assessing global HS and MaS in human liver specimens. Methods: A two-stage approach was employed on snap-frozen human liver specimens under ambient room light: biochemical validation involving a comparison of fat content from Raman and reflectance intensities with triglyceride (TG) quantifications and histopathological validation, contrasting Raman-derived fat content with evaluations by an expert pathologist and an artificial intelligence (AI) algorithm. Raman and reflectance intensities were combined to discern significant (≥10%) discrepancies in global HS and MaS. Results: The initial set of 16 specimens showed a positive correlation between Raman and reflectance-derived fat content and TG quantifications. The Raman system effectively differentiated minimum-to-severe global and macrovesicular steatosis in the subsequent 66 specimens. A dual-variable prediction algorithm, was developed, effectively classifying significant discrepancies (>10%) between AI-estimated global HS and pathologist-estimated MaS. Conclusion: Our study established the viability and reliability of a portable spectroscopic system for non-invasive HS and MaS assessment in human liver specimens. The compatibility with ambient light conditions and the ability to address limitations of previous methods marks a significant advancement in this field. By offering promising differentiation between global HS and MaS, our system introduces an innovative approach to real-time and quantitative donor HS assessments. While we made substantial strides, the true potential of this system will be fully realized through subsequent evaluations in real-world clinical settings. The proposed method holds promise of refining donor liver assessment during liver recovery and ultimately elevating transplantation outcomes.

The authors H.G., A.B.T., H.Z., I.P.J.A., and K.C.H. have filed a PCT (the Patent Cooperation Treaty) application, and they stand to benefit should the patent be awarded in the national phase.

This study was funded by the Early-Stage Commercialization Fund Phase-II, Innovacorp, Innovation Mobilization Program, and Springboard Atlantic. H.G. was supported by the Vitamin Scholarship, Dalhousie University and the Research Nova Scotia Doctoral Award, Research Nova Scotia.

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

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The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

Ethical review and approval were not required for the study at Leiden University Medical Centre on human liver specimens by the local legislation and institutional requirements. The Institutional Review Board at Vanderbilt University approved the study at Vanderbilt University (IRB #: 121423). Both studies were approved by the Health Sciences Research Ethics Board at Dalhousie University (REB #: 2022-6133 and 2022-6318).

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All data produced in the present study are available upon reasonable request to the authors