ΔE 22.4, loose: different enough that you should pick on purpose. USN Light Ghost Grey is noticeably lighter, much more muted than Trollblood Base.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 22). USN Light Ghost Grey is noticeably lighter, much more muted than Trollblood Base.
The same difference applies the other way round: Trollblood Base is noticeably darker, much more saturated.
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 Trollblood Base on the colour wheel See USN Light Ghost Grey on the colour wheel
All matches: Trollblood Base equivalents · USN Light Ghost Grey equivalents