Is anyone else having trouble with Medicaid paying for multiple ultrasounds billed with the Z36 diagnosis when you also use the Z36 diagnosis for an NT Screen as well?

We perform an initial screening ultrasound with the dx of Z36. Then perform an NT Screening with the Z36 and if we can’t see all the fetal anatomy we also perform an additional ultrasound to follow up anatomy.
What diagnosis code are you using for follow up anatomy screening, because the first ultrasound the fetal anatomy can not be viewed? Medicaid is denying this ultrasound when billed with Z36.

I appreciate any advice you can give.

Thanks!