• Can I delete information from the system?

    After your study goes live, you cannot permanently delete data from the system. Records may be archived so that they do not appear. However, all data can be retrieved, in line with GCP guidelines. The system permits soft deletion of data from an eCRF, as the data is maintained for audit trail purposes.

  • Do you support two-factor authentication?

    You can enable two-factor authentication using Google Authenticator on your account.

  • Does the system work with firewalls?

    Yes, the system is not affected by local firewalls as this is a web-based application.

  • Is the application secure?

    Security is paramount at Castor EDC. Our Security Statement explains how we keep your data secure.

  • Where and how is data stored and backed-up (e.g. clouds or servers locations)?

    All data is stored on servers in the Netherlands hosted by TRUE (, an ISO9001, ISO27001/NEN7510 certified hosting party. Certificates are available on request, for more info see Castor for European Researchers. Backups are made four-times per day and moved to a separate geographic location daily. See our Security Statement for more information.


  • Can data be exported for analysis and in what formats?

    We support SPSS, Excel, CSV, HTML. We export everything, including a code book. This means you can also easily import this into SAS, Stata, or R.

  • Can I access the system from anywhere? What internet browsers do you support?

    The system is a web application accessed with your Castor login credentials. It works with the three latest versions of Google Chrome, Mozilla Firefox, Safari, and Internet Explorer and will work on any operating system. We realize many hospitals run older versions of browsers and therefore strive to ensure all functions continue to work, although the interface might be slightly impacted.

  • Can I close or archive my study after the study is completed?

    We don’t have an explicit archive study or close study button, but you can lock (and sign) all records to ensure no changes are made.

  • Can I edit my eCRF after the study has gone live?

    Yes, you will be able to make edits to the eCRF after the study has gone live, although you must realize this will create missing data points for existing records.

  • Can I import data from my Electronic Medical Record (EMR) / Electronic Health Record (EHR) system? And how do I import old data?

    Yes, you can import CSV files with data directly into Castor EDC using our import functionality. First build your eCRF, export your empty file, fill in your existing data and import it all.

    We have constructed a HL7 FHIR based EMR importer for the Radboudumc that currently works with the Epic EHR. Contact us for more details if you are interested in doing something similar.

  • Can I upload large image files or videos?

    Castor EDC currently supports uploads up to 5 mb per file. We expect larger file storage to become available as a premium feature in the future. Please contact us if you require this.

  • Do you have an API?

    Our RESTful API is currently in beta, you can explore the documentation here:

    Contact us if you would like to use our API in your applications.


  • Do you support CDISC ODM format for importing data?

    Not currently, but stay tuned as we are working to support the following formats in Castor:

  • Does Castor EDC have (statistical) reporting?

    The system generates basic study statistics (inclusions per center, number of randomized patients, etc). We are developing a Premium Feature that will enable you to run advanced reports in the browser, contact us for more information.

  • Does the system provide logistical support for clinical trials such as scheduling patient appointments, sending text message (SMS) reminders, calling lists, etc?

    This is not core EDC functionality but for this purpose we integrate with Ldot, a logistical support tool created by MEMIC, the supporting Trial Bureau of the University of Maastricht in the Netherlands. Contact us if you would like to receive a quote for the use of Ldot in conjunction with Castor EDC.

  • Does the system support query management by study monitors?

    Yes it does. Learn more about monitoring queries here.

  • Does the system support randomization?

    We support variable, weighted block randomization with stratification using fields in your eCRF. On our short term road map are the ability to define your own block sizes as well as minimization.

  • Is anyone able to build a study in Castor EDC?

    Yes, our goal is to make building a study as easy as possible. Most people tell us the system is user-friendly, so why not try it and find out for yourself!

  • Our studies are often multi-national. Does the system provide translation to a different language?

    The interface is in English, however you can build your eCRFs in any language. The survey data entry interface is available in English and Dutch. Read more here.

  • When building the eCRF can we use a template or a previous study built in your system?

    With a Castor account, researchers can share and download other forms/templates in XML format on the Castor Form Exchange.


  • Are you ISO27001 certified?

    Castor EDC  is ISO27001, ISO 27002 and NEN7510 certified and complies with all applicable laws and regulations: Good Clinical Practice (GCP), 21 CFR Part 11, EU Annex 11, and the European Data and privacy laws, such as the coming General Data Protection Regulation (GDPR).

    Additionally we are ISO 9001 certified.

  • Do you comply with (clinical) regulations so I can run my CTIMPs (Clinical Trials of Investigational Medicinal Products) in Castor?

    There are many CTIMPS trials running in Castor EDC. Castor EDC complies with all applicable medical data privacy laws and regulations: Good Clinical Practice (GCP), 21 CFR Part 11, EU Annex 11, and the European Data Protection Directive. By using Castor EDC, researchers can comply with all GCP guidelines applicable to them in their role as sponsor and/or researcher.

  • Is Castor EDC a validated system?

    Yes, the system is compliant with ICH-GCP and fully complies with all the regulations required by FDA 21CFR Part 11 for electronic data management.

  • Is Castor EDC compliant with 21 CFR Part 11?

    Yes, Castor EDC is compliant with 21 CFR Part 11.

  • Who is the owner of the data and forms?

    As described in Article 8 of our Terms of Use, all information you input into Castor remains yours (both forms and data). If you choose to publish forms on our open Form Exchange, you explicitly allow others to make use of them.

  • Will my study be compliant with GCP (Good Clinical Practice) guidelines if I use Castor?

    As a researcher using Castor, you will comply with all GCP guidelines applicable to you in your role as sponsor and/or researcher. You can learn more here and on request, we can provide proof of validation, testing reports, certificates, etc. for the latest version of Castor EDC.

Training and support

  • Can you build my study for me?

    Yes, we provide eCRF construction services for a fee. Send us your draft eCRF and/or study protocol and we can provide you with a quote.

  • Can you give us a demonstration of the system? Are there tutorial videos?

    Register now to start exploring the system and watch our workshop videos at your own pace.

  • Do you provide one-on-one training/support in building the eCRF?

    Yes, we can provide Premium Support which includes two personal checks before your study “Goes Live” and phone support. Please contact us for more information.

  • Do you provide technical support?

    We offer two levels of support.

    1. Basic Support: support via email
    2. Premium Support: optional add-on
    – A personal session when you start building your study
    – A technical check on your study before you go “Live”
    – Priority email support
    – Phone support

  • Is training to complete the eCRF required for physicians or researchers?

    We have found that very little support and/or training is required both for constructing the eCRF and for using the data entry. We can provide customized training on-demand if you require this, please contact us.


  • Do you also provide a Clinical Trial Management System (CTMS) or Study Management System?

    Yes, we also offer Castor Study Management System (SMS), for more information see the Castor SMS website.

  • Does my department, hospital or research institute have a central (departmental) license?

    All institutions with a central license are listed in our pricing calculator. If you believe your institute is missing, please contact us.

  • I am writing a grant proposal and want to include you as a partner, do you do this?

    Yes we do. We have plenty of experience collaborating with clients for subsidies such as Horizon 2020, NHS, ZonMW, NIH and more. Contact us for more information.

  • I used Castor for my data collection, do I need to cite and how should I cite Castor in my research paper?

    We really appreciate if you cite us. We suggest using the following format.

    In text: Data was collected using Castor EDC [1]

    References: [1] Castor Electronic Data Capture, Ciwit BV, Amsterdam, The Netherlands, 2018

  • What happens if to my data if you go bankrupt or discontinue the product?

    We are growing more than 200% per year and have multi-year contracts with a growing number of top research hospitals and institutions around the globe. For insurance we have a Continuity Service arrangement with our datacenters that they will continue to run for 3 months (6 months for our UK datacenter) so that running trials are not impacted. If you require additional safeguarding measures you may become a beneficiary of our Source Code Escrow arrangement. Contact us for details.

  • What is my organization’s Billing Code?

    If your organization has an institute contract, you may contact your local Clinical Trial Unit (institute/organization Research Department) for your Billing Code.

  • What is Zoho and what is it used for?

    Zoho is an online service which we have integrated into our applications to better provide support to you, the users. To learn more about Zoho visit their FAQ page.