trial [tri´al, trīl]
a test or experiment.
an experiment performed on human beings in order to evaluate the comparative efficacy of two or more therapies. See also single blind
, double blind
, and triple blind
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.
a controlled experiment involving a defined set of human subjects, having a clinical event as an outcome measure, and intended to yield scientifically valid information about the efficacy or safety of a drug, vaccine, diagnostic test, surgical procedure, or other form of medical intervention.
Four phases of clinical trial are distinguished. Phase I trials usually involve fewer than 100 healthy volunteers who are exposed to a new drug or procedure. Such studies seek to establish optimal dosage and route of administration and to detect adverse reactions. Phase II trials generally involve 200-500 volunteers randomly assigned to control and study groups. These are pilot efficacy studies, with emphasis on immunogenicity in the case of vaccines, and on relative efficacy and safety in the case of drugs, procedures, and devices. Phase III trials, often multicenter, involve thousands of volunteers, randomly assigned to control and study groups. The aim is to generate statistically relevant data. Phase IV trials are conducted after a national drug registration authority (in the U.S., the Food and Drug Administration) has approved an agent for distribution or sale. They may explore specific pharmacologic effects, adverse reactions, or long-term effects.
Farlex Partner Medical Dictionary © Farlex 2012
A research study using consenting human subjects that tests the effectiveness and safety of a treatment, a diagnostic tool, or a prophylactic intervention.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.
clinical trial A research study involving human subjects designed to answer specific questions about the safety and efficacy of a biomedical intervention (drug, treatment, device), or new ways of using a known drug, treatment or device.
Segen's Medical Dictionary. © 2012 Farlex, Inc. All rights reserved.
clinical trial Clinical medical trial, clinical research trial Research A controlled study involving human subjects, designed to evaluate prospectively the safety and effectiveness of new drugs or devices or behavioral interventions. See Drug discovery, IND, Phase I, II, and III studies.
McGraw-Hill Concise Dictionary of Modern Medicine. © 2002 by The McGraw-Hill Companies, Inc.
clin·i·cal trial (klini-kăl trīăl)
A controlled experiment involving a defined set of human subjects, having a clinical event as an outcome measure, and intended to yield scientifically valid information about the efficacy or safety of a drug, vaccine, diagnostic test, surgical procedure, or other form of medical intervention.
Medical Dictionary for the Health Professions and Nursing © Farlex 2012
clinical trial a scientifically controlled study under specific conditions, to test, for example, the effectiveness of a drug/ treatment.
Collins Dictionary of Biology, 3rd ed. © W. G. Hale, V. A. Saunders, J. P. Margham 2005
All new drugs undergo clinical trials before approval. Clinical trials are carefully conducted tests in which effectiveness and side effects are studied, with the placebo effect eliminated.
Gale Encyclopedia of Medicine. Copyright 2008 The Gale Group, Inc. All rights reserved.
trial, randomized controlled (RCT)
An experimental design used for testing the effectiveness of a new medication or a new therapeutic procedure. Individuals are assigned randomly to a treatment group (experimental therapy) and a control group (placebo or standard therapy) and the outcomes are compared. The trial is strengthened by 'blinding' or masking (single-blind, double-blind or triple-blind study) and cross-over design. RCT is the most accepted scientific method of determining the benefit of a drug or a therapeutic procedure. It represents the best evidence available, which is integrated into the final decision about the management of a condition by healthcare practitioners in what is called evidence-based healthcare
. randomized clinical trial. See sampling
Millodot: Dictionary of Optometry and Visual Science, 7th edition. © 2009 Butterworth-Heinemann