The Centers for Medicare & Medicaid Services today issued answers to Frequently Asked Questions regarding the Healthcare Common Procedure Coding System “PO” modifier. Effective Jan. 1 under the Medicare hospital outpatient prospective payment system, hospitals that operate off-campus provider-based outpatient departments must include the modifier with the billing code for each item and service furnished in those departments. The modifier does not apply to items or services paid under other Medicare payment systems or to services physically provided at a remote location of the main hospital, according to the CMS FAQ. The modifier was voluntary in CY 2015.