Experimental tests of QFT in curved spacetime

In terms of QFT in curved spacetime (qftics), are there any known tests that confirm/void it to be a correct prescription for a first order approximation quantum theory of gravity? Obviously the extension makes some sense but how is it confirmed?

I know there are a lot of tests including Lorentz violation in qft, ultimately a possible search route to test qftics, but if there are more specific cases this would be extremely useful to know about.

1. By its very definition, QFT in curved spacetime assumes the background spacetime to be fixed and is a framework to treat quantum fields on the fixed spacetime. Hence the question "are there any known tests that confirm/void it to be a correct prescription for a quantum theory of gravity?" is ill-posed; as the mentioned formalism tells us the first-order corrections due to quantum fields only; as opposed to a full understanding of quantum gravity which would also involve taking into account how the geometry changes due to the dynamics of the fields. The key idea is that QFT in curved spacetime is the $O(1)$ correction in a full theory of quantum gravity.