Frequently Asked Questions (FAQs) about registration and reporting results for clinical trials and clinical studies

This section provides researchers with answers for the most common questions that arise with registration and reporting results for clinical trials and clinical studies.


Not all clinical studies qualify as a clinical trial under the EU Regulation. For the purpose of clarifying the requirements for registration and reporting between clinical trials and clinical studies, Karolinska Institutet (KI) uses the term “clinical trial” (klinisk läkemedelsprövning) to describe “trials that are subject to approval by the Medical Products Agency (Läkemedelsverket)”, as opposed to the term “clinical study” (klinisk studie), which describe other “interventional studies” and “non-interventional studies” that do NOT require approval from Läkemedelsverket. Information on the definition of these terms can be accessed on the "Clinical trials and clinical studies that require registration".

The Medical Products Agency (Läkemedelsverket) has specific criteria to determine if a study meets the definition of a clinical trial. Visit their website to read more about the MPA's definition and criteria for clinical trials.

The International Committee of Medical Journal Editors (ICJME) has developed an expanded definition that includes the criteria for clinical studies. Here you can access the ICJME definition that is used for clinical studies.

More information on the definition of clinical trials and clinical studies can be accessed on our webpage "Clinical trials and clinical studies that require registration".

Yes. If the study meets the Swedish Medical Products Agency’s (Läkemedelsverket) criteria for a clinical trial that involves investigational medicinal products (IMP), either under development or approved, then MPA approval is required. Researchers can determine whether their study is a clinical trial that must be approved by the MPA by reading aboutthe MPA's definition and criteria for clinical trials.

If your study meets the criteria of a clinical trial, then registration in the Clinical Trial Information System (CTIS) portal is required according to the EU regulation 536/2014. If your study meets the criteria of a clinical study, then registration on or a similarly approved clinical trial registry is required. Information to determine whether your study requires registration can be accessed at the “Clinical trials and clinical studies that require registration  webpage.

Clinical studies can be registered in prior to receiving ethical approval. However, ethical approval must be obtained before recruiting patients/participants to the study.

If you are registering a clinical trial in CTIS, everything regarding the clinical trial is managed in one system. The clinical trial application is submitted to CTIS, where the Medical Products Agency (Läkemedelsverket) and the Swedish Ethical Review Authority (Etikprövningsmyndigheten) will have access to the application. The regulatory authorities will review the application and provide feedback and decisions to the applicant directly in the CTIS portal.

The research principle (forskningshuvudmannen), responsible for registration and reporting (responsible registrant), is liable for ensuring the study is registered, updated and results are reported. Forskningshuvudmannen (responsible registrant) can either be the responsible research principal (ansvarig forskningshuvudman) who submits the ethical application, the participating research principle (medverkande forskningshuvudman) or another organization that has been allocated as the “responsible registrant”.

The Principal Investigator (PI) is responsible for the actual registration, updating, and reporting of results, whereas forskningshuvudmannen (responsible registrant) is responsible for the compliance. Detailed information regarding the responsibilities of registration and reporting can be accessed by downloading the “KI’s Clinical Trial Registration & Reporting (CTRR) Instructions” document at the bottom of this page.

A clinical trial must be registered in CTIS prior to patients/participants being recruited.

Clinical studies should be registered prior to recruitment of patients/participants is initiated, or as soon as possible afterwards. However, many clinical trial registries, e.g., allow you to register a study after recruitment has started, but it is not recommended. Many scientific journals require that a clinical study is registered in a clinical trial registry before the first patient/participant is recruited, or as soon as possible afterwards, in order for a study to be published.

Clinical trials involving investigational medicinal products (IMP) conducted in Sweden must be registered in CTIS. Karolinska Institutet (KI) recommends that non-IMP clinical studies are registered in However, researchers can also choose to register non-IMP clinical studies in any World Health Organization (WHO) approved Primary Registry or data provider.

The process for registering a new user account differs between and CTIS. Further information about this can be found on our webpages on and CTIS.

The process for registering a new study differs between and CTIS. Information on how to register a new study is described on our webpages on and CTIS.

Researchers are required to update the study registration at least once a year in In CTIS the researchers need to submit an Annual Safety Report (ASR) once a year. If there are any major changes to the study protocol (e.g., changes to individual site status or overall recruitment status), the study registration must be updated within 30 days for and within 15 days for CTIS (7 days if it’s an urgent safety measure or a serious breach).

Information on how to report results vary depending on which clinical trial registry you are reporting your results in. Detailed information on how to proceed can be found on our webpages on, CTIS and EudraCT. Researchers can also access a full tutorial on registration and results reporting in on the “PRS Guided Tutorials” website.

Results for clinical trials are required by law to be reported in EudraCT or CTIS within 12 months of the trial completion, regardless of whether the results have already been/planning to be published in a scientific journal. The Medical Products Agency (Läkemedelsverket) must be notified that the trial is completed, and results are posted on EudraCT within 90 days after study completion. You can find more on how to upload results on our webpages on CTIS and EudraCT.

Clinical studies do not require posted results by law, however, Karolinska Institutet (KI) strongly recommends that all registered clinical studies with KI as the research principle (forskningshuvudman or responsible registrant) post results in or another approved clinical registry. The purpose is to increase clinical trial transparency and thereby improving advancements in science, medicine and healthcare systems.

EudraCT is a clinical trial registry where European clinical trials were previously registered according to the EU directive 2001/20/EG. From the 31 January 2022, EudraCT has been replaced by a new web portal, CTIS. Therefore, all new clinical trials must be registered in CTIS instead of EudraCT. Ongoing trials already registered in EudraCT and where the trial is expected to be completed after 31 January 2025, need to be transferred to the new system, CTIS. For more information on transitional trials, please visit our webpage on CTIS.

However, trials already registered in EudraCT and where the trial is expected to be completed before 31 January 2025 will not be affected by this change and the results must be reported in the old system, EudraCT.

Yes. Researchers with questions concerning registration and reporting of results in the clinical trial registries, CTIS and EudraCT can contact the Compliance & Data Office (CDO) at: CDO also offers online support via Teams through a one-hour session for registration and reporting of results, for example if you want us to go through specific parts of the trial registry in more details or if you need extra support to get started on the registration/results reporting. You can schedule an appointment here.

Transparency in clinical research implies the sharing and use of clinical trial data across global registries. Greater clinical trial transparency leads to improved patient and medical care, spurs scientific innovation, and produces overall better healthcare systems. Karolinska Institutet (KI) is committed to making information about the clinical research conducted at KI both visible and accessible. In an effort to improve transparency in clinical research within open science, the University Director issued in 2020 an initiative to centralize the clinical trial registration and reporting process at KI.


Compliance & Data Office

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