Enzyme-Linked Immunosorbent Assay (ELISA) kits are complete immunoassay kits that include all reagents required to conduct the ELISA. ELISA is an assay for identifying and quantifying molecules such as proteins, antibodies, antigen, hormones, peptides. ELISA can also be used for detecting other molecules like vitamins and coenzymes. The results are quantified using antibodies linked to enzymes. There are several forms, each with its own antibody antigen interaction concept.