index patient

[ in-deks pey-shuhnt ]

noun

, Pathology.

1. the first person known to have a particular disease or other medical condition in a population, especially the first patient in an epidemic known to have contracted the infection:

   The index patient did not immediately test positive, and consequently spread the virus for several days.

Word History and Origins

Origin of index patient¹

First recorded in 1950–55

Example Sentences

Although many believe the chances are low that there was human-to-human transmission in Missouri at this point in part due to the nature of the index patient’s condition and the symptoms of those exposed, it can’t be ruled out until the final results are made public.

From Salon

The Portuguese researchers sequenced the virus from a sample collected on 4 May, which means the infected person likely had no connection to the index patient in the United Kingdom.

From Science Magazine

The CDC had requested brain tissue and cerebrospinal samples for any new cases so they could see if it was a fungus matching the one in the index patient’s body.

From Washington Times

Scientists concluded that that person infected two other families sitting at neighboring tables about three feet away; they suspect that infected droplets from the index patient hitched a ride on air flows powered by an air-conditioning system.

From Los Angeles Times

More infections cropped up on the index patient's team, which the CDC said may have been from more exposure in their separate locker room and sitting closely together on the bench.

From Fox News