[deleted_soon]

I believe you can't ever get cleared. The only way to confirm mad cow is to dissect the brain, so obviously it can't be tested for in a living person. As a result, anyone with over a certain amount of risk for mad cow can never be allowed to donate.

[gertef]

If I had leukemia, I'd love some possibly-mad-cow-tainted blood/marrow from an otherwise healthy donor.

[walshemj]

:-) I am the UK kidney transplant list last year I turned down a potential kidney as there was a risk that the donor was potentialy HIV+

The surgeons second line was "don't worry we have really good drugs for HIV these days"

In the end we agreed that given my age and I then had fairly good function left that letting some on else have it was for the best

[waqf]

You can still donate (blood, at least) for research purposes, if you can find someone who's collecting it. Bonus, you get $50–100 instead of a cookie!