Informed consent: Is it always necessary?

Informed consent plays a pivotal rote in human clinical research. It serves as a marker for the subject's comprehension of all the pertinent elements of the study. It is also a pledge by the investigator that during the trial, the rights and safety of the subject will be protected. Informed consent attempts to ensure that ethical behaviour will be upheld throughout the study. However, obtaining informed consent from certain vulnerable populations is a challenge, and thus warrants improvement. While informed consent is mandated for almost all clinical trial involving human subjects, there are situations of emergency research and trials with minimal risk that call for a waiver of the consent. (C) 2008 Elsevier Ltd. All rights reserved.