[1] Emory Univ, Sch Med, Dept Pathol & Lab Med, Atlanta, GA 30322 USA
[2] Emory Univ, Emory Ctr AIDS Res, Atlanta, GA 30322 USA
[3] AcroMetrix Corp, Benicia, CA USA
[4] Independent Stat Consultant, Philadelphia, PA USA
[5] Prov Lab Publ Hlth, Edmonton, AB, Canada