It is important to make sure your glassware is chemically clean prior to
staining for the Prussian blue reaction.  That may be a reason why the blue
appears on top of the sections.  Also, you did not mention if the liver and
spleen you were staining, were to be used eventually for control samples.
If that is the case, maybe the samples are not adequate for controls.

Hope this is helpful.
Cathy


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A GLP compliant laboratory

Cathy A. Mayton
Wasatch Histo Consultants, Inc.
www.wasatchhisto.com