My very first step is to thoroughly spray the area with a sanitiser.
Cold works up to a point, definitely use it first off but after initial cold rinsing sometimes you might find success at the other end of the scale. Go hot after all normal initial approaches though, after protein elements have been removed. Rust remover is a good tip also, phosphoric acid is the safer alternative but less aggressive, hydro
fluoric acid (don't confuse with hydrochloric) is the real deal, much more effective but don't get it on your skin!
Pre-test your stain pro, it can take colour out, ends up looking like vanish patches.
Blood technically becomes a biohazard the minute it leaves the human body I suppose. Do whatever you feel is necessary, but at least wash your hands afterwards

Steve makes a very good point - let your client know there's a high chance of a re-visit required. You can minimise this obviously by rinsing very thoroughly and drying the area off, hairdryer first then leave an airmover blowing on it whilst you pack up.
Wool is a mixed blessing, sometimes harder to remove the stain but wicking is minimal, good chance if it looks OK after 1st clean it'll be fixed with no 2nd visit.
Charge well

Last blood stain I did (sounds very similar to yours actually) on an 80/20 I took over a ton for it. But this was after qualification and discussing insurance, the last thing you want is a failed attempt and then they get whacked for their excess too. Try to steer towards insurance and let them talk you into cleaning it.
Sometimes you're more of a hero by not doing the job and saving them a hundred quid but try to leave a quote in their hand for other work before you leave
