ΔE 19.5, loose: different enough that you should pick on purpose. Fresh Blood is a little lighter, much more muted, cooler than Red Fluor.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 19). Fresh Blood is a little lighter, much more muted, cooler than Red Fluor.
The same difference applies the other way round: Red Fluor is a little darker, much more saturated, warmer.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Red Fluor on the colour wheel See Fresh Blood on the colour wheel
All matches: Red Fluor equivalents · Fresh Blood equivalents