There are many modifiers providers of therapy services are use to adding to CPT codes on the claim forms. Common modifiers include the KX modifier, 59-modifier and therapy specific modifiers of GN, GO and GP. But do you know the following modifiers and when to use them: GA, GX, GY and GZ? In this article, I will discuss when to use these modifiers on a CPT code on the claim form for therapy services. In addition, if you have additional questions on when to issue an advance beneficiary notice of non-coverage (ABN) form to a Medicare beneficiary, check out my