The GY modifier is used to denote a noncovered service. This modifier causes an automatic denial on a line item (noncovered service) for maintenance therapy.
Effective October 1, 2004 claims for covered services need not be submitted using the GY modifier. Leaving off the AT modifier automatically identifies a service as maintenance therapy. The AT modifier is discussed later in this section.
Although the GY modifier is not required, you may continue to use it if it is beneficial to your billing practices. The GY automatically drives a noncovered service, patient responsibility message, which may influence how a secondary payer pays.
If you are filing a claim for X-rays to receive a denial, you must indicate
who ordered the X-rays. Chiropractors normally order their own X-rays. Therefore,
enter your own name and UPIN in Fields 17 and 17a as the ordering physician.