isrctnorg

ISRCTN, or International Standard Randomised Controlled Trial Number, is a public registry for clinical trials that assigns unique identifiers to randomized and quasi-randomized health research studies. The aim is to promote transparency, enable linkage between trial records and resulting publications, and reduce selective reporting and publication bias.

The registry is accessible at isrctn.org and collects core information about each trial, including the registered title, condition studied, interventions, primary and secondary outcomes, study design, target sample size, eligibility criteria, locations and recruitment status, start and end dates, ethical approvals, sponsors, and funders. It supports search and filtering by fields such as condition, intervention, country, and sponsor.

ISRCTN is one of the trial registries recognized by the World Health Organization's ICTRP and by the International Committee of Medical Journal Editors. Trials registered in ISRCTN are typically registered prospectively, before participant enrolment, to document planned methods and outcomes.

The registry covers a wide range of health-related topics, including medicines, devices, procedures, and behavioral interventions, and serves researchers, journals, funders, and the public. It helps journals comply with trial registration policies and supports systematic reviews and evidence synthesis by providing a central source of trial metadata.

Over time, ISRCTN has developed governance and interoperability with other registries, remaining a major global resource for trial registration.