Monday, 17 January 2011

Legally Acceptable Representative vs Impartial Witness

ICH-GCP describes a 'Legally Acceptable Representative' as 'an individual or judicial or other body authorised under applicable law to consent, on behalf of a prospective subject, to the subject's participation in the clinical trial.' (1.37)
A Legally Acceptable Representative (LAR) only consents on behalf of a prospective subject if the subject is unable to give consent. (4.8.5).
The LAR is distinctly different from an impartial witness. in 4.8.9 ICH-GCP clearly indicates that an impartial witness is used if a subject (or the LAR) is unable to read.
Sponsor companies may request the counter signature of a witness more often than ICH stipulates, and some request it as a matter of standard procedure. Doing more than the miminum standard of ICH-GCP is certainly allowed.
The easiest way to distinguish between the function/use of the Impartial Witness vs the LAR is to think about who really consents. If it is the subject himself who consents, and is able to consent, no LAR is needed. The LAR is only intended for those situations where the subject is unable to consent. For example in case of underage (not 'of the age of consent') subjects, mentally impaired subjects or trials set in emergency situations.
In all the situations where a subject is unable to consent and still included in the trial, it was foreseeable. We don't do trials including vulnerable subjects (and a subject who is unable to consent is by definition vulnerable) unless we have no alternative, and in which case the IRB/IEC has specifically approved of the use of such subjects and of the informed consent procedure used.
A witness never consents on behalf of a subject. A witness, by signing, attests that the information in the consent form and any other written information was accurately explained to, and apparently understood by, the subject or the subject's LAR and that the consent was given gold


  1. Dear Eric,

    Your discussion is very good. Please help me clarify a doubt. Consider a subject with Cirrhosis who has developed trembling hands and cannot sign. Can he consent using an IW? Or must he use an LAR?

  2. Thanx a lot the information you provided is great sir and makes it very clear to understand.

  3. Can LAR or relatives of the subject become impartial witness. In a case of 55 year old lady subject who can not read and write but able to take decision on her own wish to participate in the diabetics trial. Her Husband accompany her during consent process and since she is unable to read the consent Investigator decides to request her husband to be an impartial witness. Is this correct.
    Next question is can subject's relative (not LAR) can be used as impartial witness.

  4. Please tell me fast Who will fill the informed consent form details like subjects initials etc