Confusing Terms and Abbreviations in Clinical Trials


Acronyms and initialisms are all too common in the clinical research industry and can help facilitate scientific communication and save time and effort for everyone involved. However, understanding and remembering a multitude of clinical trial abbreviations is a daunting task. Furthermore, the recent surge in digital systems and regulations is making it tougher to keep track of all the terms and abbreviations used in the industry.

Clinical trial abbreviations – How many can you recognize?

To better understand how the excessive use of abbreviations can sometimes be confusing and alienating, take a look at this imaginary scenario and count how many research-specific terms and abbreviations you can identify.

A DB, phase II clinical trial is initiated to evaluate the efficacy of a novel drug for the treatment of high blood pressure. An SIV is conducted at which time the CRA meets with the PI and SC at one of the sites involved in this study. Afterward, the site is approved to commence the study.

The blinded CRC recruits several patients based on the I/E criteria in the protocol. These patients are randomized into treatment and control groups. During this trial, one of the patients in the treatment group develops a stroke. The PI recognizes this as an SAE and immediately reports it to the sponsor and the IRB. A CCRC submits all the necessary data into the SD and then into the EDC.
At the end of the month, a CRA representing the CRO overseeing the study comes for a site visit and reviews the reg. binders as well as the CRFs in the EDC and completes an SDV. During her monthly monitoring visit, the CRA finds that all the information is accurate and up-to-date and complies with GCP and the CFR.

Commonly used clinical trial terms and abbreviations

Confused yet? Here is an explanation of some of the widely used terms and abbreviations, including those mentioned in our imaginary scenario, in alphabetical order:

ADE – Adverse Drug Event/Adverse Drug Effect: An adverse drug event is any unintended reaction to a drug taken at doses normally used in humans.

AE – Adverse Event: An adverse event is any negative experience during the course of a clinical trial. It can include new symptoms or the exacerbation of a pre-existing condition and may or may not have a causal relationship with the study drug.

AESI – Adverse Event of Special Interest: A specific adverse event that the study sponsor has a particular interest in, such as a known side effect of the study drug, is referred to as an Adverse Event of Special Interest. An AESI must be quickly communicated to the sponsor, often within 24 hours.

Blinding/Masking: Blinding or masking is a procedure in which one or more parties involved in the trial are unaware of the treatment assignment.

CBER – Centre for Biologics Evaluation and Research: The CBER is a division of the FDA that regulates biological products for human use.

CCRC – Certified Clinical Research Coordinator: A CCRC is a research coordinator with more than two years of clinical research experience and with certification earned by passing a required program and exam.

CDA – Confidential Disclosure Agreement (or Confidentiality Agreement): An agreement that the investigator signs in the early phases of site selection before any study information is shared with the site. A CDA states that the investigator and the site staff understand that the study information is confidential and will not share it with unauthorized persons.

CDER – Centre for Drug Evaluation and Research: The CDER is a division of the FDA that is in charge of overseeing the approval of a new drug.

CFR – Code of Federal Regulations: The CFR is a set of rules and regulations published in the federal register by the government of the United States.

CLIA – Clinical Laboratory Improvement Amendments: CLIA refers to the United States federal regulatory standards applicable to all clinical laboratory testing involving humans in the United States, except clinical trials and basic research.

CRA – Clinical Research Associate (or Site Monitor): A CRA is a person employed by the study sponsor or Contract Research Organization (CRO) to monitor a clinical study at all participating sites. The duties of a CRA may include, but are not limited to, helping to plan and initiate a study, and assessing the conduct of studies.

CRC – Clinical Research Coordinator (or Study Coordinator): A CRC is the site administrator for the clinical study. The investigator delegates the duties of a CRC.

CRF – Case Report Form: A Case Report Form is a record of pertinent information collected on each subject during a clinical trial, as outlined in the study protocol.

CRO – Contract Research Organization: A CRO refers to an organization that the sponsor contracts to perform one or more of the sponsor’s study-related duties and functions.

CS – Clinically Significant: A clinically significant finding is a finding from a subject’s medical history, physical exam, blood work, etc. that is considered to be significant in the context of the trial.

CTMS – Clinical Trial Management System: A CTMS is a software system used by the research industry to manage clinical trials.

DB – Double-blind: A Double-Blind study is a study in which all participants, including the subject, study staff, investigator, and monitoring staff, are kept unaware of the treatment assignment. Double-blind studies may require unblinded staff, such as a staff member, to mix and administer the study medication when the medication has different properties than the placebo, which could indicate the treatment assignment to blinded staff members. Blinded studies have the least risk of investigational assessment bias.

DOR – Delegation of Responsibility log: A DOR is a document that lists all the study staff members and the various trial activities delegated to them by the Principal Investigator (PI).

EDC – Electronic Data Capture: The EDC system is software that stores pertinent information collected on each subject during a clinical trial, as outlined in the study protocol.

GCP – Good Clinical Practice: Good Clinical Practice refers to an international ethical and scientific quality standard for designing, conducting, monitoring, recording, auditing, analyzing, and reporting studies. GCP principles ensure that the data reported is credible and accurate and that the subject’s rights and confidentially are protected.

HIPAA – Health Information Portability & Accountability Act: HIPAA is a law that protects the privacy of an individual’s health information and records.

ICF – Informed Consent Form: A form that documents the voluntary verification of a patient’s willingness to participate in a clinical trial, after complete, objective information, including an explanation of the study’s objectives, potential risks and benefits, alternative treatment options, and the subject’s rights and responsibilities, has been given to the subject about the trial.

I/E – Inclusion/Exclusion criteria: I/E refers to a list of criteria for entrance into a study. A subject must meet all of the inclusion criteria and none of the exclusion criteria to be included in a study.

IND – Investigational New Drug application: An IND application is a petition through which a drug sponsor requests the FDA to allow human testing of its drug product.

IRB – Institutional Review Board: An IRB is an independent group of professionals designated to review and approve the clinical protocol, informed consent forms, study advertisements, and patient brochures to ensure that the clinical trial adheres to the FDA regulations.

NCS – Not Clinically Significant: NCS refers to a finding on the patient’s medical history, physical exam, lab report, etc. that is not considered significant in the trial context.

NDA – New Drug Application: An NDA is a compilation of all the non-clinical, clinical, pharmacological, and pharmacokinetic, and stability information about a drug, which the FDA requires to approve the drug for marketing in the US.

Phase I study: This is the first of four phases of clinical trials and is designed to establish the effects of a new drug in humans. Phase I studies are usually conducted on small populations of healthy humans, specifically to determine a drug’s toxicity, absorption, distribution, and metabolism.

Phase II study: During Phase II clinical trials, a drug is tested for safety and efficacy in a slightly larger population of subjects who are afflicted by the disease in question.

Phase III study: Phase III trials involve large populations of afflicted patients and usually compare the new drug with the standard therapy currently used for that particular disease.

Phase IV study: After the FDA has approved a drug, phase IV studies are conducted to compare the drug to a competitor, explore additional patient populations, or further study any adverse events.

PI – Principal Investigator: A PI is a medical professional, usually a physician, but may also be a nurse, pharmacist, or other health care professional, under whose direction an investigational drug is administered or dispensed. A PI is responsible for the overall conduct of the clinical trial at their site.

Protocol: The study protocol is a detailed plan that sets forth the objectives, study design, and methodology for a clinical trial. An IRB must approve a study protocol before investigational drugs may be administered.

Protocol violation: A protocol violation is an event occurring in a study that is not in compliance with the protocol.

Randomization: Randomization is a process by which study participants are assigned to groups so that each participant has an equal chance of being assigned to each treatment or control group. Since randomization ensures that no specific criteria are used to assign any patients to a particular group, all the groups will be equally comparable.

Regulatory binders: Each study has a set of regulatory binders for retaining important study information, such as correspondence with the sponsor, patient logs, the DOR, old versions of the protocol, ICF, drug and equipment receipts, etc. Regulatory documents can also be stored on a digital platform in the form of an electronic regulatory (eReg) binder.

SAE – Serious Adverse Event: An SAE is any adverse event that is fatal, life-threatening, permanently disabling, or results in or prolongs hospitalization, or is a congenital disability.

SD – Source Document: A Source Document is a location where information is first recorded, including original documents, data, records, lab result printouts, etc. All the information is in the form of original records and/or certified copies of results or observations required to reconstruct and evaluate the study.

SDV – Source Document Verification: Source Document Verification is completed by the site monitor who checks the source document against what is entered in the EDC.

SIV – Site Initiation Visit: After the sponsor has selected a site to perform a study, an SIV is conducted, generally by an employee from the sponsor and/or the site monitor. The purpose of the visit is to train staff thoroughly on the protocol and any equipment that may be required so that staff can then train the rest of the involved staff members. The monitor will also go through the regulatory binders and take a tour of the facility to ensure that the study is ready to commence.

Sponsor: A study sponsor is an individual, company, institution, or organization responsible for the initiation, management, and/or financing of a clinical trial.

Sub-I – Sub-investigator: A sub-investigator works under the principal investigator to design and conduct a clinical study.

TAE – Treatment-emergent Adverse Event: A TAE is an adverse event that emerges in a subject after the beginning of study treatment.

Treatment IND: The Treatment IND is a method through which the FDA allows seriously ill patients with no acceptable therapeutic alternative to access promising investigational drugs still in clinical development. – We are here to make things easier!

It may be intimidating to wrap your head around so many abbreviations and acronyms. However, we at, understand the importance of enabling our clients to reduce errors and conduct trials efficiently. This condensed list of commonly used abbreviations is our attempt to help you expand your understanding of clinical trials. Whether you are new to the industry or need a refresher, go through this cheat sheet to find an explanation of any obscure abbreviation that you may come across.

Would you please let us know if we missed something important so we can amend this list?