Background: Rapid, objective phenotyping of donor organs is an unmet need in kidney transplantation, particularly when comparing donation after circulatory death (DCD) with donation after brain death (DBD). We tested whether Fourier-transform infrared (FTIR) spectra of the static cold-storage preservation solution collected from kidney allografts capture discriminative biochemical signatures of donor type.

Methods: Perfusates from Celsior-preserved kidney allografts (n=10; 5 DCD/ 5 DBD) were analyzed in the Fourier transform infrared (FTIR) spectroscopy mid-infrared (Amide I and fingerprint regions). After standard quality control and normalization, spectra underwent routine derivative processing. Supervised classifiers were trained and assessed with cross-validation to evaluate discrimination between donor types.

Results: FTIR spectroscopy of perfusate revealed donor-type signatures. Pipelines combining derivatives with non-redundant feature selection consistently improved discrimination. The fingerprint region outperformed Amide I. In cross-validation, models achieved high performance, with area under the curve up to 0.84–1.00 and accuracies up to 1.00 within this pilot; the best pipeline reached perfect in-cohort discrimination.

Conclusions: Perfusate FTIR spectroscopy provides a rapid, economic label-free readout that could complement pump parameters and metabolomics during organ perfusion. Given the small, matched pilot and heterogeneous spectral quality, larger, standardized, multi-site studies with rigorous internal validation and assessment of instrument/site transferability are required before clinical deployment.