International Clinical Trials Registry Platform (ICTRP)

Linking related records on the ICTRP Search Portal

The ICTRP Search Portal provide a single point of access to information about ongoing and completed clinical trials using records made available by data providers around the world. Because of the varying requirements for trial registration around the world, many multinational, multicentre trials are registered in more than one registry. In such cases the ICTRP Search Portal receives more than one record for those trials.

To reduce confusion and as a service to aid in the unambiguous identification of trials, the ICTRP Search Portal attempts to bridge (group together) such multiple records about the same trial. It does this by matching main trial identifiers to secondary trial identifiers found in trial records. The ICTRP Search Portal shows that it has found a group of records about the same trial by displaying a plus (+) sign in its search results:

Clicking on the (+) sign shows the other records referring to the same trial. Note that the record with the earliest date of registration is always shown first.

This method will unambiguously identify trials if trials registries ensure that all known identifiers for a trial are recorded.