Regulations enforced by FDA require that as part of the suitability criteria, a donor be free from any disease transmissible by blood transfusion, in so far as can be determined by health history and medical examination. FDA periodically issues guidance providing recommendations to decrease the potential for transmission of infectious disease when new information or testing methodology becomes available. In August, 1999, FDA issued guidance for Industry entitled, "Revised Precautionary Measures to Reduce the Possible Risk of Transmission of Creutzfedlt-Jakob Disease (CJD) and New Variant Creutzfeldt-Jakob Disease (nvCJD) by Blood and Blood Products". After reviewing the comments received, FDA further revised the guidance on November 23, 1999. A copy of the most recent revised guidance is available at http://www.fda.gov/cber/gdlns/cjdvcjd.pdf. The guidance states that, "FDA believes that donors who have resided in the United Kingdom (as identified by questions in section III.D) may be at risk for exposure to nvCJD. As a precaution, FDA recommends that donors who have spent six months or more cumulatively in the United Kingdom from 1980 through 1996 (i.e., from January 1, 1980 through December 31, 1996) be indefinitely deferred." FDA takes a conservative approach to ensure the safety of the Nation's blood supply and therefore, issues guidance relating to both known infectious diseases as well as potentially emerging diseases. This conservative approach may result in the deferral of otherwise acceptable donors. FDA recognizes that the scientific technology for determining individuals at risk for CJD and nvCJD, and detecting the infectious agents in tissues and in products, is continuing to advance, and that there may be a need for future updating of the relevant guidance. | 
