When should re-consent of subjects participating in a clinical trial be requested? A case-oriented algorithm to assist in the decision-making process.

Investigators, sponsors, and institutional review boards have to decide when re-consent of clinical trials' participants must be obtained when new information becomes available. We present an algorithm to help in the decision-making process, which takes into consideration the kind of new information, the risk of exposure (patients could be on the treatment or in the follow-up phases), and the possibility of managing the case. Re-consent should be obtained in three of the eight possible situations.