Quidel Corporation is engaged in the development, manufacturing and marketing of diagnostic testing solutions. These diagnostic testing solutions primarily include applications in infectious diseases, women's health and gastrointestinal diseases. The Company sells its products directly to end users and distributors, in each case, for professional use in physician offices, hospitals, clinical laboratories, reference laboratories, universities, retail clinics and wellness screening centers. It markets its products in the United States through a network of national and regional distributors, and a direct sales force. Internationally, it sells and markets primarily through distributor arrangements. Its diagnostic solutions are used in the detection and diagnosis of many critical diseases and other medical conditions, including infectious diseases, women's health, autoimmune diseases, bone health, thyroid diseases and fecal occult blood.