Visit identifiers

A visit identifier defines the type of visit.

A visit is identified by two pieces of information: the visit value and visit unit. The visit value is a sequential identifier, such as a number. The visit unit is the type of visit.

For example, a visit of “3 WK” indicates that it is the third visit of the week type. The 3 is the visit value, and WK is the visit unit. The protocol in which the participant is enrolled likely has defined specimen collections for this visit.

The available visit units are defined by various projects that use LDMS. Users cannot create their own visit units.