Dr. Yun-Fu Hu,

Another possibility is that there is increased melanin present as a
result of the disease process and which would cause background.  Perhaps
you could try a different enzyme label such as alkaline phospatase which
gives a red end product.

Hermina

--
Hermina Borgerink, BA, HT(ASCP)IHQ
Department of Pathology
Wake Forest University School of Medicine
Winston-Salem, N.C. 27157
PH (336) 716-1538
Fax (336) 716-1515