The American Association of Blood Banking (AABB), on June 18, 2010, issued a Bulletin to its member blood collectors requesting that ME/CFS patients be actively discouraged from donating blood because of the "risk of transmission of XMRV" (Xenotropic Murine-Related Virus). In October, 2009 the journal Science published a study which presented evidence of an association of XMRV with ME/CFS. In making this recommendation, the AABB is concerned about the safety of the U.S. blood supply.  

[2015 editiorial note: Even though it was disproven in 2012 that ME/CFS patients are infected with XMRV, it is prudent to refrain from donating blood or tissue due to the high probability of being carriers of other infectitious agents. See p. 30 of ME/CFS: A Primer for Practicing Clinicians.]