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AMA Citation Style 11th Edition Guide

Citing Trial Registries

General Trial Registry Format 


Author/Group Title Registry Name ID Identifier Date Posted/Update Date accessed URL
Author AA, Author BB. Title of trial. Registry name identifier: XXX###. Updated Month Day, Year. Accessed Month Day, Year.
Group Name. Title of trial. Registry name identifier: XXX###. Posted Month Day, Year. Accessed Month Day, Year.

Trial Registry Specific Notes: 

  • Include the Trial Registry identifier after the Registry name as shown in the examples
  • Common registries include: (US), (Australia and New Zealand), (UK), (the Netherlands), (Japan), and EU Clinical Trials Register/ EudraCT (Europe)
  • If there is not an author or group associated with the trial, you can start the reference with the title of the trial (like example 2).


General example:

1. Author AA. Title of trial. identifier: NCT123456. Updated April 1, 2021. Accessed November 2, 2021.

Specific Example:

2. Evaluation of phage therapy for the treatment of Escherichia coli and Pseudomonas aeruginosa wound infections in burned patients (PHAGOBURN). identifier: NCT02116010. Updated July 23, 2015. Accessed October 13, 2016.

3. Rizzardini G. Clinical Study To Evaluate The Performance And Safety Of Favipiravir in COVID-19. identifier: NCT04336904. Updated April 8, 2020. Accessed June 15, 2020.

4.German Cancer Research Center. Use of acetylsalicylic acid (ASA) for enhanced early detection of colorectal neoplasms. EudraCT Identifier: 2011-005603-32/DE. Posted May 30, 2012. Accessed November 2, 2019.