Question: Are we allowed to report a nurse practitioner’s (NP) services to Medicare with a locum tenens modifier? He is filling in for one of our NPs who is on medical leave following surgery. Codify Subscriber Answer: No, you cannot report modifier Q6 (Service furnished under a fee-for-time compensation arrangement by a substitute physician; or by a substitute physical therapist furnishing outpatient physical therapy services in a health professional shortage area, a medically underserved area, or a rural area) to Medicare for an NP’s service. Here’s why: Modifier Q6 was originally designed to represent locum tenens (or substitute) services of one physician for another, but the modifier does not apply to nurse practitioners. Keep these tips in mind when filing claims that do qualify for modifier Q6: Final note: Modifier Q6 has no effect on payment.