Non-invasive detection of total bilirubin based on multi-wavelength PPG signal

Background and objective: Abnormal bilirubin metabolism can result in various liver function disorders. Current clinical practice for bilirubin level detection involves invasive blood collection from patients, which is time-consuming, painful, and poses infection risks. Thus, there is a pressing need for non-invasive bilirubin detection methods. This study aims to develop a non-invasive total serum bilirubin(TSB) detection method in humans based on multi-wavelength photoplethysmography (PPG) signals.Methods: The experimental instrument includes a light source and a spectrometer. PPG signals are col-lected from the subjects' fingers, and the samples are selected based on the PPG deviation degree screen-ing method. The absorption spectrum of blood is extracted from the PPG signal using dynamic spec-troscopy. Finally, locally developed software calculates the total bilirubin value. The instrument is mod-eled and validated according to the clinical-biochemical test values.Results: The results of the prediction set (correlation coefficient is 0.91, RSMEP is 2.32 umol/L, average absolute error percentage is 9.3%) show that our method has a strong correlation with the detection re-sults of clinical-biochemical analysis instruments. The Bland-Altman test showed that the device deviated from the data detected by biochemical methods in the clinic with a mean deviation of about 0.12 umol/L and a 95% confidence interval between-2.95 umol/L and 2.7 umol/L.Conclusions: This study's non-invasive bilirubin detection method has high accuracy, which can meet the needs of continuous non-invasive total bilirubin detection in clinical practice.(c) 2023 Elsevier B.V. All rights reserved.