1. From the Departments of Laboratory Medicine and Pathology (B.T.L., J.J.M., W.D.E.) and Medicine (L.T.C.), Mayo Clinic, Rochester, MN; the Department of Pathology, University of Arizona, Tucson, AZ (R.E.S.); the Department of Surgery, Missouri Heart Center, Columbia, MO (V.E.T.); University Hospital Southampton, UK (S.G.D., C.R.P., I.A.S.); and the Department of Laboratory Medicine and Pathology, Mayo Clinic, Scottsdale, AZ (H.D.T.).