Each clinical trial must have a unique trial number. This requirement is cited in a number of publications including:
- The Declaration of Helsinki of the World Medical Association (revised October 2013 Brazil) states: "Every research study involving human subjects must be registered in a publicly accessible database before recruitment of the first subject."
- The International Committee of Medical Journal Editors (ICMJE) stipulated that from July 1st 2005, "no trial will be considered for publication unless it is included on a clinical trials registry so it can be tracked from initial protocol through to publication."
The World Health Organisation (WHO) regards trial registration as the publication of an internationally agreed standard dataset about a clinical trial on a publicly accessible database managed by a registry conforming to WHO standards. The standard dataset is published by the WHO International Clinical Trials Registry Platform (ICTRP).
The ISRCTN registry helps researchers fulfil research transparency and result dissemination objectives, as per the requirements set out by the WHO ICTRP and the International Committee of Medical Journal Editors (ICMJE), by listing the basic set of data items deemed essential to describe a study at inception and by providing the unique identification number necessary for publication.The NIHR Portfolio Database facilitates ISRCTN registration for eligible studies. Additional information can be found on ISRCTN registration on the Clinical Research Network. Alternatively, trials may be registered at ClinicalTrials.gov.
The EudraCT number is an additional mandatory reference number allocated by the European Medicines Agency (EMA) for CTIMPs authorised on or after 1 May 2004 (see EudraCT Number station).
Guidance on trial registration and research project identifiers can be found on the HRA webpages.