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Frequently Asked Questions


Additional questions about managing study records may be sent to staff (


Is there a charge for listing studies on

No, there is no charge for listing studies on is a free service of the National Institutes of Health, provided through the National Library of Medicine.

My study is not yet approved by a human subjects review board (ethics review committee, institutional review board). Can I enter it on

Most trials require approval from a human subjects review board. If your study requires approval, you may register your study on prior to getting approval if the Overall Recruitment Status of the study is "Not yet recruiting." See Overall Recruitment Status data element on .

If a study requires human subjects review board approval, approval must be obtained before the study's Overall Recruitment Status is changed to Recruiting. When board approval is obtained, please update the protocol section of the study record in the Protocol Registration System (PRS) and release the study for processing.

See How to Register Your Study and How to Edit Your Study Record for more information.

Why can't I find my study on

It might not have been released (that is, submitted) to for processing. After a record has been entered into PRS (or has been modified) and marked as Complete, it must be Approved and Released by the Responsible Party (see Responsible Party data element on )

It might be undergoing review. After the Responsible Party releases (submits) information to, that information undergoes a manual review to identify possible errors, deficiencies, or inconsistencies that are not detected automatically during data entry. The Responsible Party will be notified of any necessary corrections, usually within a few days after release of the protocol information. The review of results information may take longer (up to 30 days), depending on the quantity and complexity of information submitted.

See How to Register Your Study and How to Submit Your Results for more information.

When will the NCT Number for my study be assigned?

The NCT Number, also called the Identifier, is assigned after the protocol information has been released (that is, submitted) by the Responsible Party and passed review by staff. At that time an e-mail notification with the NCT Number is sent. The record, including its NCT Number, will typically be available on within 2–5 business days after it is released.

See How to Register Your Study for more information.

Can I register a study after it has started, has closed to recruitment, or has completed?

Yes, you can register a study on at any time. Please note that, in general, Section 801 of the Food and Drug Administration Amendments Act (FDAAA 801) requires Applicable Clinical Trials to be registered within 21 days of enrollment of the first participant. In addition, the International Committee of Medical Journal Editors and other journals require registration of clinical trials prior to enrollment of the first participant.

See FDAAA 801 Requirements for more information.

Must clinical studies with no external sources of funding ("unfunded" studies) be registered at

The registration requirements of Section 801 of the Food and Drug Administration Amendments Act (FDAAA 801) (PDF)and the International Committee of Medical Journal Editors (ICMJE) policy on the Obligation to Register Clinical Trials under the Uniform Requirements for Manuscripts do not exclude clinical studies with no external sources of funding ("unfunded" studies). See FDAAA 801 Requirements for more information on which trials must be registered under FDAAA 801.

In general, an unfunded study should be registered via the PRS account of the Sponsor. When an investigator is considered the Sponsor (that is, a Sponsor-Investigator), the study should be registered using the PRS account of the investigator's affiliated institution with the Responsible Party indicated as "Sponsor-Investigator." will then display the investigator as the Sponsor instead of the investigator's institution. The Data Element Definitions on describes the related data elements for Responsible Party.

How do I contact if I have a question about my study record?

If you have questions or need assistance with how to update your record, you may email staff ( If the question is about a specific study record, please provide the NCT Number or the Unique Protocol ID (if an NCT Number is not yet assigned). Please include sufficient information about the issue so that we may better assist you. We generally respond to all emails within one business day.

Protocol Registration System (PRS) Accounts

Can an organization have multiple users in a single account?

Yes. When sponsors or their representatives register to become PRS data providers, they will be given information on using PRS, including instructions for creating additional user accounts.

See How to Apply for an Account for more information.

FDAAA 801 - Section 801 of the Food and Drug Administration Amendments Act

To comply with FDAAA 801, must I submit information to, or can I use another registry or results database?

You must use to fulfill the requirements of FDAAA 801 (PDF). FDAAA 801 requires Responsible Parties to submit clinical trial information to the Director of the National Institutes of Health (NIH) for inclusion in the registry and results databank established as

Does FDAAA 801 only apply to Industry-sponsored studies?

No. FDAAA 801 applies to any clinical study that meets the definition of an Applicable Clinical Trial and that was initiated after September 27, 2007 or that was initiated on or before that date and still ongoing as of December 26, 2007. FDAAA 801 does not distinguish between types of sponsors or funding sources in establishing requirements for registration and results submission.

For complete statutory definitions and more information on the meaning of Applicable Clinical Trial, see Elaboration of Definitions of Responsible Party and Applicable Clinical Trial (PDF).

Does the definition of Applicable Clinical Trial under FDAAA 801 only include studies conducted under an FDA Investigational New Drug Application (IND) or Investigational Device Exemption (IDE)?

No. A clinical investigation of a drug can be an Applicable Drug Clinical Trial under FDAAA 801 even if it does not require an IND, and a clinical investigation of a device can be an Applicable Device Clinical Trial whether or not an IDE is required.

See Elaboration of Definitions of Responsible Party and Applicable Clinical Trial (PDF) for more information.

Uploading Study Data to

Can protocol information be uploaded electronically to

Yes. This option is available in PRS as an HTTP upload of an Extensible Markup Language (XML) formatted file. After obtaining a PRS account, login to PRS and refer to the User's Guide for information on XML upload.

See How to Apply for an Account for help with obtaining a PRS account.


Am I required to submit the results to of a clinical trial that is not an Applicable Clinical Trial?

Results submission is not required under FDAAA 801 for a clinical trial that is not an Applicable Clinical Trial (for example, a phase 1 trial studying a Food and Drug Administration (FDA)-regulated investigational new drug). If a Responsible Party chooses to voluntarily submit results for such a trial, however, the Voluntary Submissions (PDF) provision of FDAAA 801 may apply.

Under the Voluntary Submissions (PDF) provision, a Responsible Party who submits results for such a clinical trial must submit complete clinical trial results information and must also submit results for each Applicable Clinical Trial that is required to be submitted to FDA under Section 505, 510(k), 515, 520(m) of the Federal Food, Drug, and Cosmetic Act or Section 351 of the Public Health Service Act for the same use studied.

How do I submit results information if the trial is terminated (that is, stopped prematurely) and no data were collected for one or more outcome measures?

If no participants were ever enrolled in the trial, set the Overall Recruitment Status to "Withdrawn", and no further results information needs to be submitted.

For a trial that was terminated after participants were enrolled, provide any available data. If no data are available for any of the Outcome Measures, specify zero ("0") for the Number of Participants Analyzed in each Arm/Group, and leave the data fields blank. In this case, provide an explanation in the Analysis Population Description for why zero participants were analyzed and, if appropriate, provide information in the Limitations and Caveats module. Even if data are not entered for Outcome Measures, submit the available data for the enrolled participants in the Participant Flow, Baseline Characteristics, and Adverse Events modules.

I completed a clinical trial that studied an investigational product (drug, biological product, or device that is not initially approved, licensed or cleared by the US FDA). There is no intent to seek approval, clearance, or licensure of the product by the US FDA (for example, development of the investigational product has been terminated). How do I indicate that results need not be submitted for this trial?

The Responsible Party may "Certify Initial Approval" in the PRS. This indicates that the clinical trial completed before a drug, biological product, or device studied in the trial was initially approved, licensed or cleared by the FDA (for any use).

This page last reviewed in December 2012