I believe past discussion about giving blood within EA has undervalues doing so and hopefully the reasoning laid out here will show why.
Some caveats first; I think that some of the reasoning used here may only apply to certain blood groups: i.e. universal donors, additionally past discussion has focused on QALYs and reaches a different conclusion to me - it may be that using different metrics leads to different conclusions or that my method is flawed however due to the limited information about the stats of giving blood and limited discussion within EA (2 posts one against and one for blood donation being effective as far as I can tell) means having a discussion at al could be useful.