Which term means no known cause?

• A. TTP
• B. CT Scan
• C. Endoscopy
• D. Idiopathic

Answer: (D)

When a condition has no identifiable cause after thorough evaluation, the term used is idiopathic. This label signals that, despite testing and assessment, no etiologic factor has been found. The other terms describe either a specific disease process (a defined hematologic disorder) or a diagnostic procedure (an imaging test or an endoscopic examination) and do not convey anything about etiology. Idiopathic is the best fit because it directly means “no known cause.” In practice, many idiopathic conditions exist, such as idiopathic pulmonary fibrosis, illustrating how a diagnosis can be made even when the cause remains unknown.