ΔE 10.9, fair: the same colour family, but not a straight swap. Thick Blood is a little lighter, more saturated, cooler than Bloodreaver Flesh. They are different kinds of paint: Citadel Bloodreaver Flesh is an opaque base/layer paint and Vallejo Thick Blood is a fluorescent or effect paint, so they won’t behave the same on the model even where the colour is close.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 11). Thick Blood is a little lighter, more saturated, cooler than Bloodreaver Flesh. They are different kinds of paint.
The same difference applies the other way round: Bloodreaver Flesh is a little darker, more muted, 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 Bloodreaver Flesh on the colour wheel See Thick Blood on the colour wheel
All matches: Bloodreaver Flesh equivalents · Thick Blood equivalents