Hi Andreas,

you can use a variety of agents to block aspecific sites in IHC technique.

We used even complete culture medium with 10% fetal bovine serum (diluted 1:10 for ICC) when for instance purified albumin was not available to prepare the standard blocking reagent.

So if you are sure no interference may be foreseen with your antibodies, I think you can use this serum to be diluted and used as blocker.

Also rather than putting the entire slide into i.e. block or antibody solution buy a hydrophobic pen and draw around the sample and add the block/antibody to that (for a typical section you use ~100-200 ul (or less).

See: http://www.sigmaaldrich.com/catalog/product/sigma/z377821?lang=en®ion=GB

You need to keep the slide in a hydrated dish however (I put the slides in a sealed plastic box (Tupperware) with wet tissue at the bottom with the slides resting flat on that (to stop the small volumes drying out over night at 4oC).

Thanks guys, I used to use a fat/filt-pen, but now I use floting sections again. The the tissue is stained on all sides, then you can do stereology on it.

Still, no answer on how to make your own serum(blocker) from centrifuged blood.

If any have tips on how to prepare, conserve the serum please write.