[Histonet] Inconsistent immuno staining

[Ann Bennett]

Hello Histonetters,
 
While trying to eliminate any variables - processing times, embedding paraffin, waterbath temperature, time and temp in oven, deparaffinization, antigen retrieval, antibody manufacturer and lot # - I still seem to have a slight inconsistency with 1 of my immuno stains.
 
Mast Cell Tryptase staining for colon biopsies.
 
Can anyone offer any suggestions or ideas as to why this might be occuring?
 
Even within my current control slides I see a nice distinct brown or a slightly more pale stain.
 
I would love to hear your ideas.
 
Thank you!
 
Ann.BennettAnn