Which modifier would be billed as primary?

[Wendy3221]

If you are coding for a 45380 and 45385 - which was originally a screening but changed to these with the findings, and commercial insurance, Would you bill the 33 first and then the XS modifier or vice versa?

 

[mconner001]

Code the modifier that impacts payment first. In this case the XS goes first - then the 33.