ΔE 19.8, loose: different enough that you should pick on purpose. Cardinal Purple is a little darker, much more muted, cooler than Bloodmoon Red.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 20). Cardinal Purple is a little darker, much more muted, cooler than Bloodmoon Red.
The same difference applies the other way round: Bloodmoon Red is a little lighter, 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 Bloodmoon Red on the colour wheel See Cardinal Purple on the colour wheel
All matches: Bloodmoon Red equivalents · Cardinal Purple equivalents