This document discusses electrochemiluminescence (ECL) technology, which is a detection method for immunoassays. ECL involves applying a voltage to induce a light-producing reaction from ruthenium complexes bound to immunological complexes. This allows for precise, non-isotopic, automated assays with low detection limits. Some key advantages of ECL include excellent sensitivity comparable to older methods but without radioisotopes, simple and rapid measurement, stable reagents, and applicability to a wide variety of analytes and assay types. ECL systems have high clinical quality and are becoming more widely used for immunological testing.