[1] Blood Ctr Pacific, San Francisco, CA USA
[2] GenProbe Inc, San Diego, CA USA
[3] Amer Red Cross, Natl Confirmatory Testing Lab, Gaithersburg, MD USA
[4] Westat Corp, Rockville, MD USA
[5] Univ British Columbia, Victoria, BC, Canada
[6] Univ Calif San Francisco, Dept Lab Med, San Francisco, CA 94143 USA