ΔE 15.9, loose: different enough that you should pick on purpose. Blood Thorn is noticeably darker, cooler than Blood Moon Red.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 16). Blood Thorn is noticeably darker, cooler than Blood Moon Red.
The same difference applies the other way round: Blood Moon Red is noticeably lighter, 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 Blood Moon Red on the colour wheel See Blood Thorn on the colour wheel
All matches: Blood Moon Red equivalents · Blood Thorn equivalents