Non-Invasive and Cost-Effective Fecal Occult Blood Detection for Colon Cancer Prognosis in Murine Models.

Fecal occult blood testing is a widely used diagnostic method for the early detection of colorectal cancer and the assessment of gastrointestinal pathologies in humans. For preclinical research purposes, we developed a cost-effective, non-invasive luminol-based chemiluminescent assay to detect fecal occult blood in murine feces that can function as a predictive tool, with sufficient sensitivity to correlate with disease severity. Fecal samples were collected and weighed, solubilized in a sodium hydroxide solution, then combined with luminol and hydrogen peroxide and immediately analyzed using a luminometer. Luminol reacts with the iron in hemoglobin to produce a measurable chemiluminescent signal; therefore, known hemoglobin concentrations from mouse blood, quantified using a hemoglobinometer, were used to generate a standard curve along with feces from naïve mice. The method was validated against standard Guaiac paper slide tests for accuracy. We demonstrated a strong correlation with disease severity metrics, including colonoscopy findings and tumor burden in multiple models of colon cancer, offering an accessible, non-invasive, and inexpensive alternative for routine monitoring of disease progression. The application of this technique can be broadened to other murine models of gastrointestinal pathologies, such as peptic ulcers, inflammatory bowel disease, Crohn's disease, and gastritis.