Radiology Coding Alert

CMS provides two HCPCS modifiers that radiology coders should append when billing Medicare for services that are likely to be denied. When used correctly, the modifiers allow the physician to submit charges to a secondary payer or directly to the patient after Medicare's denial.

CMS introduced the two modifiers in January of this year. Modifier -GY will be used to report an item or service statutorily excluded or does not meet the definition of any Medicare benefit, while -GZ will describe an item or service expected to be denied as not reasonable and necessary. Modifiers -GY and -GZ replace modifier -GX , which was used in many situations. The new modifiers more clearly define the reasons for denial.

Modifier -GY is intended for services that Medicare, by law, can't pay for. These services are assigned a status code of N in the Medicare Fee Schedule and include many screening evaluations such as routine chest x-rays (see related story) or cardiac scoring (an investigational procedure often reported with 76499, Unlisted diagnostic radiologic procedure).

On the other hand, coders would append modifier -GZ when national or local Medicare policy has excluded specific services as not reasonable or necessary and no ABN has been obtained from the patient. An example is bone density scans (e.g., 76075, Dual energy x-ray absorp-tiometry [DEXA], bone density study, one or more sites; axial skeleton [e.g., hips, pelvis, spine]), which are not covered unless certain prerequisites have been met. When modifier -GZ is appended to the service, the patient usually cannot be billed for any balance Medicare doesn't pay. Modifier -GZ is completely voluntary, but it alerts the Medicare carrier that the practice is not attempting to claim payment for services that are not medically necessary.

Note: Modifier -GA (Waiver of liability statement on file) is used when the radiology practice expects a denial and has an ABN on file.

When these modifiers are reported, Medicare knows practices are not trying to beat the system and obtain inappropriate reimbursement, but rather that they know it isn't covered and need an explanation of medical benefits (EOMB) to confirm the denial.