[Histonet] IHC blocking for liver tissue

[Amy Lee]

Hello,
 
I have a question that what is best way to block endougenous biotin and HRP in liver or kidney tissue. The method I am using has to use avidin-biotin and HRP reactions. This is fine on heart tissue.  I used biotin blocking kit from DAKO or Vector. Also I used 1% H2O2. But liver tissue still show background stain.
 
Could you teach me a better way to block or is there other reason cause background?
 
Thanks in advance,
 
Amy