Biotest AG engages in the development, production, and marketing of biological medicinal products used in the treatment areas of hematology, clinical immunology, and intensive care medicine. It operates through the following segments: Therapy, Plasma & Services, and Others. The Therapy segment consists of the development and production of blood plasma based markets immunoglobulin's, clotting factors, and albumins. It also includes the pre clinical and clinical development of monoclonal antibodies, indications for which include rheumatoid arthritis and blood cancer. The Plasma & Services segment includes the areas of plasma sales and toll manufacturing. The Others segment include retail business and costs. The company was founded by Carl Adolf Schleussner and Hans Schleussner in 1946 and is headquartered in Dreieich, Germany.