As far as I know it's only a conscience matter in that you can take it and they probably won't disfellowship you
Accepting whole blood or what Watchtower labels as its primary fractions is not considered by Watchtower to be a conscience issue. What they label as a matter of conscience is accepting what they label as "secondary fractions" of blood - fractions of fractions.
Also, a person who is found to have unrepentantly accepted blood is disassociated from the congregation. There's practically no difference between that and disfellowshipping. The distinction that Watchtower is attempting to make is purely for technical legal reasons. By way of illustration if we liken being disfellowshipped to being shot by someone; and disassociating to shooting yourself. Then being disassociated by the congregation is like someone putting a gun in your hand and forcibly pointing your hand with the gun at your head and squeezing your trigger finger.