(Clinical Decision Support System) An application that supports a physician's diagnosis and treatment. A CDSS that uses a knowledge base of symptoms helps doctors diagnose the patient, while a drug knowledge base helps them prescribe medicines that do not conflict with other drugs the patient is taking. Instead of a knowledge base, a CDSS may use algorithms that evaluate random solutions in order to find the one that seems best. A Daunting Task Developing a CDSS that integrates with the organization's systems and utilizes even a fraction of the volume of medical information being published is a daunting task. However, the Health IT for Economic and Clinical Health Act (HiTECH) requires that healthcare providers implement a DSS rule for ordering diagnostic tests by 2015. See healthcare IT.