index case

1. 1.

   the earliest documented case of a disease that is included in an epidemiological study

   Broaderpatient

   epidemiology

Questions about index case

What does index case mean?

index case means "the earliest documented case of a disease that is included in an epidemiological study".

Is index case a common word?

index case is banded "Rare" — specialist or archaic — most readers will not have met it. The band comes from how often the word appears in a large corpus of everyday English, not from an editor's impression.