We have an immuno problem. We use the Vector Elite detection system with DAB
as chromogen. In the past couple of weeks sections have been turning green
when we apply the DAB. After counterstaining there is specific staining but
it is usually black as opposed to the expected brown colour. This problem
seems to be confined to sections without any antigen retrieval. Sections
that have been treated with enzymes or heat are staining fine. I would
appreciate any suggestions. I've turned green myself trying to come up with
an answer.

Tony O' Grady
Dept. of Pathology
RCSI Education and Research Centre
Smurfit Building
Beaumont Hospital
Dublin 9
Ireland
Tel. (353 1) 8093716
Fax. (353 1) 8093720
Email. togrady@rcsi.ie