ΔE 13.3, fair: the same colour family, but not a straight swap. Topaz Skin is a little darker, more muted than Matt Blood Red. They are different kinds of paint: AMMO by Mig Matt Blood Red is an ink, glaze or transparent paint and Army Painter Topaz Skin is an opaque base/layer 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 13). Topaz Skin is a little darker, more muted than Matt Blood Red. They are different kinds of paint.
The same difference applies the other way round: Matt Blood Red is a little lighter, 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 Matt Blood Red on the colour wheel See Topaz Skin on the colour wheel
All matches: Matt Blood Red equivalents · Topaz Skin equivalents