Enzyme-linked immunosorbent assay (ELISA) is a commonly used analytical immunoassay technique involving detection of an analyte normally when there is a demand for measurements on a smaller scale and/or lower sensitivity which can be very cost-effective. Although the radioimmunoassay (RIA) method is similar in principle to the non-radioactive sandwich ELISA method, it uses radiolabeled molecules thereby making it extremely sensitive and extremely specific. This method can be used for any biological molecule in principle and is not restricted to serum or plasma antigens. Because radioactive substances are used it requires special precautions and licensing in combination with specialized equipment. Arcadia is utilizing this technique on a wide variety of projects involving high sensitive screening for hormone levels in blood samples.