We have been having trouble with our immunoperoxidase
staining.  The chromogen has been getting lighter and
lighter in staining until finally today I had no staining.
We thought maybe it was the pH of our Na Acetate buffer, but
when we pH'ed it it was right on at 5.18.  Our next hurdle
will be to make the Secondary Link up again.  We use a
dilution of 1:400 (using rabbit and mouse immunoglobulins).
Has this happened to anyone else?  If so any feedback would
be appreciated.

Amylin Johnson, HTL
Associates in Pathology
Wausau WI