"I have no problem with the cops taking blood"
I have a real problem with this as it is against the 5th amendment. No one is recquired to give evidence against themselves, no matter if it's murder or petty theft. This shouldn't stand a court challenge.
The SCOTUS already revoked the fifth amendment.
Giving blood is not self-incrimination, any more than is giving your name. Sorry, that case was decided long ago.