A novel optical assay system for bilirubin concentration measurement in whole blood

TL;DR

This paper presents a compact, low-cost optical system for measuring bilirubin levels in whole blood, enabling more accessible and continuous monitoring outside clinical settings, especially for high-risk cirrhotic patients.

Contribution

The study develops and optimizes a dual-wavelength transmission setup for accurate bilirubin measurement in small blood samples, suitable for point-of-care applications.

Findings

High correlation (R^2 > 0.95) between measured and actual bilirubin levels.

Measurement accuracy within +/- 1.7 mg/dL, reliable for concentrations > 4 mg/dL.

System is economical, compact, and suitable for portable bilirubin monitoring.

Abstract

As a biomarker for liver disease, bilirubin has been utilized in prognostic scoring systems for cirrhosis. While laboratory-based methods are used to determine bilirubin levels in clinical settings, they do not readily lend themselves to applications outside of hospitals. Consequently, bilirubin monitoring for cirrhotic patients is often performed only intermittently; thus, episodes requiring clinical interventions could be missed. This work investigates the feasibility of measuring bilirubin concentration in whole porcine blood samples using dual-wavelength transmission measurement. A compact and low-cost dual-wavelength transmission measurement setup is developed and optimized to measure whole blood bilirubin concentrations. Using small volumes of whole porcine blood (72 {\mu}L), we measured the bilirubin concentration within a range corresponding to healthy individuals and cirrhotic patients (1.2-30 mg/dL). We demonstrate that bilirubin levels can be estimated with a positive correlation (R-square > 0.95) and an accuracy of +/- 1.7 mg/dL, with higher reliability in cirrhotic bilirubin concentrations (> 4 mg/dL), critical for high-risk patients. The optical and electronic components utilized are economical and can be readily integrated into a miniature, low-cost, and user-friendly system. This could provide a pathway for point-of-care monitoring of blood bilirubin outside of medical facilities.