I looked at this the other day, there was something that I couldn't put my finger on that wasn't 'right'...?
I think there are two things, maybe three ...
Splat, rather than drop - even dripped form a relatively short distance, blood 'splats' even if only vertical ther should be a 'splatter pattern'
The 'consistency' doesn't look right - too many small random drops?
Too much emboss, making it appear thick and gel-like?
Colour - fresh - bright red, dried - dark red/brown/black, dried would have soaked in to any porous material and therfore not have a visible meniscus.
The shadow is inconsistent with the main image ( I realise this may just be a 'test', so no big deal)
Having said that, I don't think it's too far away
I'm going to have a quick play and see if I can illustrate what I'm trying to say... \:]