  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.
