Radioimmunoassay, more commonly referred to as RIA in short, is a diagnostic technique used to analyze clinical samples in blood banking, endocrinology, and allergy testing. In the clinical lab, specific RIA assays can be used to test hormones (e.g Adrenaline, Noradrenaline, and more), drugs, hepatitis B surface antigen, and anti-DNA antibodies in systemic lupus (SLE). Although, radioimmunoassays involve handling of radioactive antigens, RIA diagnostic assay tests are widely used as they provide great sensitivity.