Asymptomatic, early-stage, cancer detection is a problem in the small intestine, that is largely inaccessible. This paper presents a cost-effective screening capsule prototype, which is able to detect infrared (IR) fluorescence emitted by indocyanine green (ICG) fluorophore dye. The presented mixed-signal system has a small size, consumes little power and works as a high-sensitivity fluorometer that records fluorescence levels throughout the small intestine, rather than collecting images that need labour intensive video analysis. Ex-vivo experiments, on ICG-impregnated swine intestine, have shown that the prototype system is able to detect low concentrations of ICG in the nanomolar and micromolar region, which is required to detect early cancer in the small intestine.