Used in immunological research to quantify complement factor D levels in biological samples such as serum, plasma, or cell culture supernatants. Enables study of the alternative complement pathway activation, which plays a role in immune defense, inflammation, and autoimmune diseases. Widely applied in clinical research to investigate conditions like age-related macular degeneration, atypical hemolytic uremic syndrome, and other complement-mediated disorders. Supports drug development and biomarker validation by providing a reliable method to monitor CFD concentration changes in response to therapeutic interventions.