TUNEL false positive - (Nov/22/2008 )

Hi,
I have the same problem with islet tissue paraffin sections (fixed with PFA). There are high false positive, even I diluted TdT 100 times. Do you find a solution to this problem?
Thank you very much.
Zhongyan

ah tunel, how I hate thee. Are you using a tunel kit? coverslips inbetween every step and wash wash wash. I use 4-5 washes inbetween every step that requires washing. Also, do you block for endogenous peroxidases? what about protein blocking?