Index testing, also referred to as partner testing/partner notification services, is an approach whereby the exposed contacts (i.e., sexual partners, biological children and anyone with whom a needle was shared) of an HIV-positive person (i.e., index client), are elicited and offered HIV testing services.
In this context, index testing refers to any HIV testing of the contacts of an index client (i.e., a person known to be HIV positive).
Source: https://indicatorregistry.unaids.org/