<<Disclaimer: Verify this information before applying it to your situation.>>

It is true that if gf diet is working, than no, you don't need a test.
You are healthy.  The value of more definitive tests is for people who
are sure they are gf, but still not feeling well.  Do they need to track
down those last few molecules of gluten, or do they have another problem
which is coincidentally somewhat allieviated on a gf diet?  I avoided
fats and dairy for years becuase those foods gave me the discomfort
(funny, though, that the worst trouble came from the ghee in Indian food,
which I always ate with tons of bread, and plain yogurt, though
disgusting, was less troublesome than bread with yogurt in it) - I was
unaware of a problem with gluten per se, since I was never off it.  But
gluten does seem to be the actual culprit.  For others, something about
the gf diet may help (maybe their main source of dairy or egg is in baked
goods?), but the actual culprit is ?  Those folks could use a test that
works without the need to encounter whatever is riding along with the
gluten.

Elizabeth