The Renin ELISA is a solid phase enzyme-linked immunosorbent assay (ELISA) based on the sandwich principle.

The microtiter wells are coated with a monoclonal [mouse] antibody directed towards a unique antigenic site of the human active Renin molecule.

An aliquot of patient sample containing endogenous Renin is incubated in the coated well together with Assay Buffer.

After incubation, unbound components are washed off.

Finally, Enzyme Conjugate, which is a monoclonal anti-Renin antibody conjugated with horseradish peroxidase, is added, and after incubation, unbound enzyme conjugate is washed off.

The amount of bound peroxidase is proportional to the concentration of Renin in the sample.

Having added the substrate solution, the intensity of color developed is proportional to the concentration of active Renin in the patient sample.