Enzyme ImmunoAssay (EIA) is a technique to detect and quantify antigens (proteins, hormones…) or antibodies in samples. It relies on the ability of an antibody to bind a specific antigen. Either the antibody or the antigen is labelled with an enzyme whose substrate is a chromogen or a fluorogen converted in a measurable product (color or fluorescence).|Enzyme-linked Immunosorbent Assay (ELISA) is a type of EIA using a solid phase (ex: microtiter plate) coated with an antigen immobilizing the molecule to detect. Over the time, scientists have extended the term ELISA to EIAs using an antibody coating the solid phase. That explains why our EIA kits using coated antibodies are also called ELISA kits.|The Renin-Angiotensin system (RAS) is essential for the control of blood pressure and homeostasis. It plays an important role in cardiovascular and renal disorders. Among the different peptides resulting from the proteolytic processing of angiotensinogen (the only substrate of Renin), the octapeptide Angiotensin II (AII) is the major hormone involved in the pathophysiology of hypertensive diseases as it mediates vasoconstrictor action.|Angiotensin I is the precursor of Angiotensin II. It is a decapeptide without apparent physiologic effect. It is converted in Angiotensin II by the Angiotensin-converting enzyme (ACE).|The peptidic sequence for Angiotensin I is highly conserved across mammalian species, this is why our kit cross-reacts with all mammalian samples.