Used in biomedical research to measure angiotensin I levels in biological samples such as plasma or serum. Helps in studying the renin-angiotensin system (RAS), which regulates blood pressure and fluid balance. Enables researchers to assess RAS activation in experimental models of hypertension, heart failure, kidney disease, and other cardiovascular conditions. Provides a reliable, sensitive, and quantitative method for monitoring changes in angiotensin I concentration in response to drugs, dietary factors, or disease states. Commonly used in preclinical studies and drug development.