Who owns and runs ISRCTN?

The ISRCTN registry is owned by ISRCTN, a company limited by guarantee set up in 2005. It is controlled by its Board of Directors, which delegates day-to-day management of the registry and database to the editorial team. It has the benefit of advice from an international advisory group. The ISRCTN registry is administered and the database is hosted and published on behalf of ISRCTN by BMC, a publisher of open-access peer-reviewed biomedical journals. BMC is owned by Springer Nature.

What is the purpose of ISRCTN?

The ISRCTN was set up to register clinical trials, provide each one with a unique identifying number, and make the registry records publicly accessible and searchable. ISRCTN was founded in response to calls for the registration of studies as a condition of publication in a journal, and also in response to the recognition that the results of many studies remain unpublished and, without registration, remain hidden from the scientific record. For further discussion of the importance of study registration, please see Why register?.

What does ISRCTN stand for?

When the registry was started in the early 2000s, the acronym stood for International Standard Randomised Controlled Trial Number because the scope of the Registry was randomised controlled trials (RCTs). Over the years the scope has been expanded (see scope below) and the acronym now means International Standard Registered Clinical/soCial sTudy Number. However, the preferred name is simply ISRCTN and not the spelt out version.

What is the scope of ISRCTN?

The scope encompasses any study designed to assess the efficacy of health interventions in a human population. This includes both observational and interventional studies.

Which organisations does ISRCTN work with?

ISRCTN works with a number of stakeholders to improve the information publicly available about clinical studies. See our Resources page for more details.

Where does ISRCTN funding come from?

Some registries, such as those that are part of the WHO network may not charge a fee because their activities are fully funded by grants. The ISRCTN registry is not funded by an overall government grant and is not the result of legislation. To ensure that clinical study information is listed freely, a fee is charged for the publication of the information describing a study at inception.

What does the ISRCTN fee cover?

The fee covers the cost of maintaining a public registry which is free to access. The fee is set at a level that enables the ISRCTN editorial staff to maintain the registry and to support researchers in providing complete information, including patient-friendly content.

The fee per study is paid either by the researchers themselves or by the institutions they belong to. The main UK funders of health research regard this fee as an allowable research cost.

For the current fee, please read the section entitled 'What is the fee for registration'.

How and when to obtain an ISRCTN

How do I obtain an ISRCTN?

To apply for an ISRCTN, click on Register on the home page or go to the login section. After login the application has four stages: study details, contacts, sponsors/funders, and payment agreement. Details for all fields are on the Definitions page. Once your application has been received, a member of the ISRCTN editorial team will contact you with any questions on the details of your study. Once your study details are in line with editorial policies and we receive payment, we will assign an ISRCTN and will include your record immediately in the ISRCTN registry. Submission of a record to the ISRCTN registry assumes that the applicant has read and agreed to the terms and conditions for ISRCTN study registration.

When should a study be registered?

A study can be registered at any stage and it is never too late or too early to register. However, guidelines strongly recommend that studies be registered before patient enrolment begins, and some journals require prospective registration if they are to publish a study. As the ISRCTN registry holds a system-generated date of registration as well as the recruitment start and end dates, the records will show whether the study was registered retrospectively or prospectively.

Which studies should be registered?

The ISRCTN registry provides ISRCTNs for any clinical study designed to assess the efficacy of health interventions in a human population. This includes both observational and interventional studies. All designs are eligible.

Which studies cannot be registered?

Studies that are not clinical studies in a human population, including:

  • Case reports (a case series with a predefined research plan or protocol is acceptable)
  • Animal studies
  • Meta-analyses
  • Systematic reviews
  • Studies with no outcomes measured in humans

Do you accept studies of traditional medicine (e.g. Chinese medicine, acupuncture)?

ISRCTN accepts studies of any intervention, but please note that studies of traditional medicine from any country can now register free of charge at the new International Traditional Medicine Clinical Trial Registry, which has joined ISRCTN as part of the WHO Registry Network. It has editors specialising in traditional medicine and accepts submissions in either English or Chinese. ITMCTR is the recommended registry for traditional medicine studies.

Should pilot studies be registered?

Although not all pilot studies go on to become full studies, we recommend that pilot studies should be registered provided the study is designed to assess the efficacy of a healthcare intervention(s).

What happens when the pilot study becomes the main study?

If the pilot study has already received an ISRCTN, there is no need to make a new submission as long as the main study is an expansion of the pilot study and has the same participant(s), intervention(s), and outcome(s), with the results of the pilot and main study expected to be published in one article. A new ISRCTN is required otherwise. This is to facilitate transparency and enable accurate searching.

How do I decide whether the study requires more than one ISRCTN?

Please contact the ISRCTN editorial team for any special case.

How long will it take to obtain an ISRCTN?

Once you have submitted your application, the ISRCTN editorial team will review your application within two working days and request any further details if necessary. Getting an ISRCTN with inclusion in the ISRCTN registry then depends on the speed of payment.

Using the ISRCTN

When do I use an ISRCTN?

The ISRCTN should be recorded on all study documentation (e.g. protocol, study forms, patient leaflets, reports, etc). It should be quoted where appropriate in publications, conference presentations, correspondence relevant to the study and references to the study (e.g. new grant applications). If the study is also registered in another (e.g. a specialist) registry, the ISRCTN should be quoted in the other registry. This will aid in de-duplication between registries. You should notify study co-funders and other sponsoring partners (e.g. companies supplying drugs or other materials to the study, overseas co-operating or collaborative partners etc).

Note that the ISRCTN does not replace the study acronym. Nor is the study acronym a replacement for the ISRCTN. They should not be used interchangeably.

How do I refer to an ISRCTN?

When referring to an ISRCTN, there should be no space between the ISRCTN and the number itself.

How do I cite an ISRCTN study record in a publication?

All ISRCTN records have digital object identifiers (DOIs). To cite an ISRCTN study record in the reference list of an article, please include named authors, year of publication and title of study according to the convention of the publication, followed by the DOI, e.g.:

Mendelow, AD (2006): Surgical Trial in Lobar Intracerebral Haemorrhage. ISRCTN. https://doi.org/10.1186/ISRCTN22153967

When do I use the ISRCTN itself and when do I cite the ISRCTN using the DOI?

If you are publishing the protocol or your results of a study, quote the ISRCTN itself in the paper (e.g. in the abstract, or according to the journal’s guidelines). If you are referring to a study registration record in the reference list of a paper, use a formal citation of the DOI.

What happens if there are two ISRCTNs for the same study?

If you notice that two or more ISRCTNs have been assigned to a study, please contact the ISRCTN editorial team to inform them of this duplication. We will advise on the best solution and keep all relevant parties informed. ISRCTNs that are taken out of use will not be re-assigned to another study.

Registering a study

How do I register a study?

The ISRCTN application process has five steps (including login). Please see the Definitions page for details about the information required and go to the ISRCTN registry home page.

How do I get a study registered quickly?

The ISRCTN registry will prioritise the processing of studies that require prompt registration, provided that the minimally required information is provided. This guidance explains the steps you can take to enable same-day registration.

What information is needed to register my study?

The information requested is in line with the WHO dataset. The full dataset for the ISRCTN registry is listed and explained on the Definitions page.

What if I don’t have all the information to hand?

You can save your application and return to it later. Please note that the details you enter are only kept for 3 months if you don’t complete your registration.

Can I register if I do not have ethics approval?

Even if your ethics approval is pending you can register with ISRCTN. During the submission, in the ethics approval field, please mention that your ethics application is in progress.

When you have received your ethics approval, please provide us with the name of your ethics board, the contact details of the ethics board including mailing address, telephone number and email address, the date of your ethics approval, and any reference numbers attached to this approval. This can be done after an ISRCTN has been assigned to your study but should be updated before your first participant is recruited.

What is needed for the plain English summary?

One aim of promoting transparency in health research is to support public understanding of science and public trust in high-quality research findings. The ISRCTN registry aims to make content more accessible and easy to understand via a plain English summary. In order for the text to be written in very plain English (and not as an abstract for a peer-reviewed paper) ISRCTN recommends the use of the guidance developed and used by Cancer Research UK.

What do I have to do if my study is in the NIHR Portfolio database?

If your study has already been adopted by the NIHR and fulfils the eligibility criteria, the charge for registering your study with an ISRCTN will be invoiced to the Department of Health and Social Care.

Please note that your study could be adopted by the NIHR Portfolio, but may not meet the eligibility criteria e.g. it takes place elsewhere in the UK (i.e. Northern Ireland, Scotland or Wales), is an observational study or is industry-supported/industry-sponsored. In this case you will have to pay the registration fee.

In order to register for ISRCTN through the NIHR Portfolio, you need to access your record on CPMS and follow their instructions: tick yes to the question ‘Would you like to register this study for an ISRCTN’ and a message should provide information on whether your study is eligible for ISRCTN registration funded by the Department of Health and Social Care/NIHR.

The NIHR Portfolio team will then send us your study for ISRCTN registration and you will not need to complete an application directly with us. The NIHR Portfolio team sends us weekly batches of studies for ISRCTN registration. We would usually receive the study within 1 to 2 weeks if the above instructions are followed.

The Be Part of Research Registration Service can support recruitment to NIHR-funded or -supported studies. More than 250,000 research-ready participants are signed up to take part in health and social care research. This free service can identify volunteers for your study through the wide range of data it collects including age, ethnic group, sex, location and condition. Visit Be Part of Research to find out more.

What do I need to do to register my study through the UK HRA partnership with the ISRCTN registry?

Please read the guidance on the Resources page and the HRA website:

How do I apply for deferred registration of a UK Phase I study?

Please read the guidance on the Resources page and download the following PDFs:

  • Summary guidance on uploading minimum fields for deferred trials (download PDF)
  • Detailed guidance for applicants on uploading minimum fields for deferred trials (download PDF)


Licence to Post

What is the aim of the ISRCTN registry's approach to licensing and copyright?

The ISRCTN registry exists to keep in a standard format a freely accessible and searchable record of each registered study. The Terms and Conditions enable anyone to cite with attribution the details in each study record. They encourage unrestricted use of the metadata generated during the process of registration, updating or reporting.

What is a Licence to Post (LTP)?

A Licence To Post (LTP) defines what a researcher (a ‘Responsible Registrant’) agrees to, when submitting study details (called the ‘Contribution’) to the ISRCTN registry. The LTP is available here.

Who is a Responsible Registrant?

A Responsible Registrant is the appropriate representative of the study sponsor. As a Responsible Registrant, you ensure that the initial Contribution is complete, accurate and meaningful to meet registration standards. You confirm that you are responsible for keeping the study details up-to-date and that you have the right to post and update the Contribution on behalf of the study team.

How can I agree to the LTP?

A standard text is included in the first email which you as the Responsible Registrant will receive from the ISRCTN system after the submission of a Contribution. By emailing to ISRCTN or otherwise continuing the registration process, you acknowledge that you agree to the LTP described here.

Am I assigning copyright to ISRCTN when I acknowledge the LTP?

No, there is no transfer of copyright. As a Responsible Registrant, you retain the right to the data from study inception to findings dissemination. The LTP gives ISRCTN a licence to post and confirms that users are able to make use of your study details under a CC-BY licence.

What is a CC-BY licence?

Creative Commons was developed to facilitate open access as defined in the founding documents of the movement, such as the 2003 Berlin Declaration. Using Creative Commons helps share scientific work. The CC BY licence (see https://creativecommons.org/licenses/by/4.0/) allows readers (users) to copy, distribute and transmit the Contribution as long as it is attributed back to the researcher who provided it and/or is mentioned as Contact(s) in the Contribution. Readers are permitted to alter, transform or build upon the Contribution, and to use the Contribution for commercial purposes, as long as the source of the Contribution is provided, as well as the date it was obtained from the ISRCTN registry.

More on how to cite an ISRCTN record on http://www.isrctn.com/page/faqs#usingISRCTN.

What is a CC0 waiver?

The CC0 waiver (see https://creativecommons.org/publicdomain/zero/1.0/) allows readers (users) to copy, distribute and transmit the metadata without restriction. The person who associated a work with this deed has dedicated the work to the public domain by waiving all of his or her rights to the work worldwide under copyright law, including all related and neighbouring rights, to the extent allowed by law.

Does agreeing to the LTP mean that you peer-review my Contribution?

No, the contribution is not peer-reviewed (as is the case for a manuscript) but undergoes internal review. The ‘Responsible Registrant’ is responsible for the content of the Contribution (whether at initial submission or during future updates). The ISRCTN editorial team checks it for compliance with the following guidelines:

  1. ISRCTN editorial policy: https://www.isrctn.com/page/faqs#registeringStudy
  2. WHO International Standards for study registration: https://apps.who.int/iris/bitstream/handle/10665/274994/9789241514743-eng.pdf
  3. International Committee of Medical Journal Editors ICMJE statements on clinical trials: http://www.icmje.org/recommendations/browse/publishing-and-editorial-issues/clinical-trial-registration.html
  4. Clinical research reporting guidelines listed by the EQUATOR network: http://www.equator-network.org/.

Note: The Contribution may include links to third-party sites and file attachments. ISRCTN will check that the links and attachments are relevant for the Contribution in question but ISRCTN is not responsible for the accuracy and quality of the links and the files and the fact that they may include some personal information.

Does the LTP allow me to remove the Contribution from the ISRCTN registry?

No. Registration is strongly recommended but not legally required in a number of countries. This means that Contributions are usually submitted voluntarily, in agreement with a number of international and national guidelines and policies. Once a study has been publically posted on the ISRCTN registry, the study will remain permanently on the registry and cannot be removed. This is in order to fulfil the primary objective of a registry, which is to limit publication and outcome reporting biases. It is always possible to update a Contribution and information about what has been updated will be included in the ISRCTN record.

Why is there a fee to post a Contribution?

There are costs at several stages of the study registration process, from administering the editorial review and sending reminders at key milestones, to hosting the contribution on dedicated servers and allowing users to freely read and search for information. The fee allows the contribution to be published open access under a Creative Commons licence.

Fee details are available at https://www.isrctn.com/page/faqs#payment.

What happens to the LTP when I update the Contribution?

When updating your Contribution you confirm your agreement to the CC-BY licence and CC0 waiver for metadata as described here.

The Responsible Registrant can contact ISRCTN at any time to request updates to the Contribution. ISRCTN will have the right to contact researchers, either at key milestones or whenever the needs arise, to ensure that the Contribution remains up-to-date in line with international standards. The content of an update is the responsibility of the Responsible Registrant and will follow the same review as the initial contribution.

Does the LTP allow the sharing of Contributions on other platforms?

Yes, by virtue of the CC-BY licence and CC0 waiver for metadata.

Where else is the study data being used?

ISRCTN is a primary registry in the World Health Organization (WHO) Registry Network (http://www.who.int/ictrp/network/primary/en/) and sends weekly data feeds to ICTRP and all Contributions to ISRCTN will appear on the WHO ICTRP search portal (http://apps.who.int/trialsearch/). To ensure your study can be sorted by location on ICTRP, make sure that the 'Countries of recruitment' in your ISRCTN record are up to date.

ISRCTN is an acknowledged data source for Be Part of Research and all the contributions that include a research site in the UK will appear on the Be Part of Research site (https://bepartofresearch.nihr.ac.uk/). If your study is recruiting in the UK, make sure that the 'Study participating centres' in your ISRCTN record are up to date so that these are displayed to potential participants on Be Part of Research.

Your Contribution can be used on any platform as long as it is correctly attributed as per the CC-BY licence.

What will happen with the LTP when a new Responsible Registrant takes over the study?

ISRCTN acknowledges the fact that the Responsible Registrant may change over the course of a study. The new Responsible Registrant will comply by default with the licensing terms agreed by the initial Responsible Registrant.

What will happen to my Contribution if ISRCTN ceases to exist?

Should the ISRCTN registry cease to function, the Contribution would be transferred to another registry in the WHO Registry Network. Your Contribution would be covered by the Terms and Conditions of the new registry.


Checking and updating a record

How do I keep track of my draft studies?

By logging in and reviewing records displayed in the 'My Studies' section.

Can I remove a record from the registry?

Once a study has been registered on the ISRCTN registry and publicly displayed on the website, the study will remain permanently on the register and cannot be deleted.

When does a record need to be updated?

The ISRCTN registry will update a record on request at any time. For example, it will be necessary to record the conclusion of a study when known, and to report the publication of findings or to add summary results. Also, it may be appropriate to amend a record after ethics approval has been granted, to update the start and end dates of the study if there has been a delay to the start of the study, and to update the funder and sponsor details if the study has been extended, and the previous funding has run out. If the WHO 24-item minimum dataset or the ICMJE guidelines evolve, it may also be necessary to update the record to ensure that it is in line with these guidelines.

Some of the older records in the ISRCTN registry may not be complete according to the current WHO 24-item minimum dataset. The ISRCTN editorial team regularly reviews records for completeness and will contact record providers if missing information is noted. If you request an update to an older record, the ISRCTN editorial team may take the opportunity to request a more extensive update to ensure that your record complies with current WHO/ICMJE guidelines.

What do the green/yellow/clear/grey badges on records mean?

Registry records now display green badges to highlight good transparency practices. The BEEP study is an example that has several green badges.

  • If a study is registered before the recruitment start date it earns the prospective registration badge
  • If you add a link to or upload a protocol the study earns the protocol badge
  • If you add a link to or upload a statistical analysis plan (SAP) the study earns the SAP badge
  • If you add a link to results of any kind or upload a basic results summary the study earns the results badge
  • If you add a link to a raw dataset the study earns the raw data badge
  • If your study record is ongoing and has been updated in the last year the study earns the ‘updated in the last year’ badge

Yellow badges are displayed where the item might need attention, e.g. when the study is ongoing but has not been updated in the last year or when results have not been added to an interventional study and it is 1-2 years after the overall study end date, or for when best practice has been partially followed, e.g. when the study has been registered retrospectively.

The red badge for results is intended to draw attention to interventional studies that have no results linked or uploaded at 2 years or more after the overall study end date. 

Clear badges are displayed when the study is at a stage where the item is not expected (e.g. raw data and results are not expected when the study is ongoing, and regular updates to the record are not expected once the study is completed)

Grey badges are displayed when items are not expected to be added because the study has been stopped.

How do I edit or update my record?

If you wish to update your ISRCTN record, please contact the ISRCTN editorial team or use the update request form or the results reporting form. Please note that we cannot remove information from a record, or overwrite previous information, but will instead add any updated information, along with a date stamp to show when the changes were made to the study record.

How will I know when my record has been updated?

Once you have contacted us with your requested update, a member of the ISRCTN editorial team will make the updates to your study record, and will inform you via email once these are done. A link to your record will also be provided to ensure that you can check over the changes.

How long will it take for my record to be updated?

An update to a record can usually be performed within two working days, depending on the size of the update


How do I pay for registration?

Registrants can pay by credit or debit card, cheque or bank transfer (please note that we do not accept Western Union money transfers). However, we strongly recommend that payments are made by credit or debit card, as they generally clear more quickly than other forms of payment.

At submission you will be able to choose between three options:

  • Online payment: Please select if paying by debit or credit card
  • Offline payment: Please select if the registration fee is to be paid by bank transfer or cheque and fill in the required information. Bank transfer payments take up to 30 days after the transfer date to be confirmed by our Accounts Department. Payments by cheque can take up to 15 days to clear
  • Funder pays: Please only select if your funder or sponsor has arranged an agreement with ISRCTN to pay for the registration directly (e.g. the NIHR or Wellcome Trust)

Are any taxes included in this charge?

Invoices issued to UK billing addresses will be subject to Value-Added Tax (VAT), currently 20%.

Invoices issued to billing addresses outside the UK will be subject to local taxes if applicable. Where a tax-reverse charge mechanism is in place, registrants will be given the opportunity to provide a reverse charge number, allowing them to receive a tax-free invoice and to pay tax in their billing country instead.

Who is responsible for making the payment?

Whoever submits the application is responsible for making or arranging the payment (for instance, via his or her institution).

What is the fee for registration?

The fee is listed when you get to the payment section of the application process. The fee is GBP250 + tax when applicable. Offline payment has an administrative surcharge of GBP20 + tax.

For organisations

Can an organisation set up an account with ISRCTN?

In order to expedite and streamline the process of registering studies with an ISRCTN, organisations can set up an institutional account in order to pay for study registration monthly or use a prepay method. Studies from the organisation can then be registered immediately (pending any questions on the study information), with no need to arrange payment before the ISRCTN is allocated. Please contact the ISRCTN editorial team for further information.

What reports do organisations receive?

Organisations with an ISRCTN account receive a yearly report of all studies registered within the year. Please contact the ISRCTN editorial team if you have special reporting requirements.

Finding study information

How do I use the ISRCTN registry to find relevant studies?

You can search or browse the entire database – please see our guidance

Can I display my search results visually?

The transparency tracker provides a visual display of the transparency achieved by a set of records, found by a search of the registry. From any search results page click on ‘View in tracker’ to see the search results displayed in the transparency tracker. Click on the bars of the bar charts or the slices of the pie charts to filter the search results.

How do I download data from the ISRCTN registry?

You can download search results in CSV format or retrieve data using the ISRCTN XML API. Please see the API documentation here for more details (note this is a draft and may be incomplete, if you have any feedback please contact the ISRCTN editorial team).