Educational Content: This article is for informational purposes only and does not constitute medical advice. Always consult a healthcare provider for diagnosis and treatment.
Definition of Index case
Medically reviewed by Min Clinic Staff | Updated: January 2026
Index case: A person who first draws attention to his or her family because of having a medical condition. For example, if an eye doctor discovers a person has glaucoma, and subsequently other cases of glaucoma are found in the person's family, that person is the index case. Also known as propositus (if male) or proposita (if female).