We had the same issue a few years ago with the Ventana HP antibody. Then we tried the antibody from Zymed and it was so much better. Now we use BioCare's antibody, and it is very clean. Terri L. Braud, HT(ASCP) Anatomic Pathology Supervisor Laboratory Holy Redeemer Hospital 1648 Huntingdon Pike Meadowbrook, PA 19046 ph: 215-938-3689 fax: 215-938-3874