Our test for roan is only a "marker test", meaning we test for a DNA sequence variant that is present in most (but not all) roans. It works well for ponies, Gypsy cobs and QHs descended from Sir Cool Skippin. It does not work for other QH lines.
Roan is a coat pattern where white hairs are mixed with coloured hairs over most of the body. It is different from grey in a few ways: roan horses are roan from their first foal shed, and unlike greys don't become progressively lighter as they age. The head and points are generally solid coloured without the even mixture of white hairs seen on the body, and in many cases roaning on the legs ends with a distinctive upside-down V on the front of the knees. Roan summer and winter coats can appear quite different from one another.
When roan horses get skin injuries on their bodies, the scarred area grows back in their base coat colour without roaning, leaving visible marks.
Gene or region and technical reference
Gene: KIT (marker). Reference: Marklund et al. (1999)
n. Test developed using animal controls.
Rn. Test developed using animal cases.