Suppose your practice’s primary physician goes on a two-week vacation. You bring in a substitute healthcare practitioner to ensure continuity of patient care. Services are delivered, encounters are documented, and now it is time to file a claim. But, how exactly do you bill services in such a scenario? Do you use the National Provider Identifier (NPI) of the physician on vacation or file a claim with the substitute’s NPI? That’s where many billers get confused.
The Q6 modifier solves that problem, but only when you use it correctly. A single mistake on the claim form can trigger a denial or, worse, an audit. We have created this guide to help you use this important modifier correctly. So, let’s start.
Q6 Modifier – Description
The Q6 modifier is defined as:
“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.”
The definition is self-explanatory, but let’s expand on this. Basically, Q6 tells Medicare that the services on the claim were not delivered by the physician named on the billing account. Instead, the practice or facility hired a temporary substitute physician, also referred to as a locum tenens physician, who provided care on a fee-for-time basis.
Actually, the Latin word “locum tenens” literally means “holding the place”. In medical billing, this word is used to describe a licensed physician who is not part of a practice but is temporarily hired to fill in for the regular physician for some time.
This temporary placeholder physician is paid on an hourly basis and is not an employee of the healthcare practice. Billing does not change much due to this. The insurance claim is submitted with the name and NPI of the permanent physician, just with one difference. Q6 is appended to each procedure code.
Scenarios Where Q6 Modifier is Applicable
Let’s make things clearer with some examples. Here are a couple of real-world scenarios in which modifier Q6 can be used:
Physician Out On Medical Leave
Suppose a primary care physician himself gets sick. He decides to rest and recover at home for at least 4 weeks. So, he takes a month’s medical leave. To fill in the gap, the practice hires a licensed but temporary physician. Until the regular physician returns, this new physician will look after all patients. The practice pays this physician on an hourly basis, and he has no separate patient panel of his own.
In this case, the practice files all claims under the regular physician’s NPI, appending the Q6 modifier to each procedure code. The substitute’s NPI is kept on file at the practice and made available to Medicare upon request.
Physical Therapist On Her Maternity Leave
Suppose a pregnant physical therapist who is employed at a hospital’s outpatient physiotherapy department in a rural area takes 8 weeks off for the delivery of her baby and postpartum rest. In her place, the hospital hires a male licensed physical therapist who cares for her regular patients while she is away.
In this case, locum tenens billing rules are used, and the claims are submitted with the female physical therapist’s name, NPI number, and the Q6 modifier appended to CPT codes. The substitute is paid per hour by the hospital for his services.
Q6 Modifier – Billing Guidelines
Here are some additional guidelines that you must follow when using the Q6 modifier in your claims:
- First, verify that the substitute physician qualifies. The locum tenens physician must hold an active, unrestricted medical license in the state where services are provided. They must also be enrolled in Medicare. You cannot use Q6 for a provider who has not yet been credentialed. Billing with Q6 during the credentialing process is considered non-compliant with Medicare rules and can result in repayment demands or audit exposure.
- Second, use the correct claim form fields. On Form CMS-1500, place the Q6 modifier in Box 24D alongside the relevant CPT or HCPCS procedure code. The regular physician’s NPI must appear in Box 24J as the rendering provider. Failing to fill both fields correctly is one of the most common causes of Q6-related claim denials.
- Third, pay the substitute physician on an hourly or fee-for-time basis only.
- Fourth, observe the 60-day continuous billing limit. According to CMS, the Q6 modifier may only be used for a continuous substitute period of up to 60 days. If absence extends beyond that, the regular physician can only bill the first 60 days with Q6. The locum tenens must then bill the remaining services under their own NPI and name. One important exception exists: if the regular physician is called to active military duty, the 60-day cap does not apply for that entire absence period.
- Fifth, maintain complete internal records. The practice must keep a log of every service the substitute physician provided, matched to that physician’s NPI. This record does not need to appear on the claim form, but Medicare reserves the right to request it during an audit.
- Sixth, this modifier is only applicable to physicians. You cannot use it for non-physician practitioners like CRNAs, NPs, and PAs. There is just one exception to this rule. You can use it for physical therapists in a health professional shortage area (HPSA), a medically underserved area (MUA), or in a rural area.
Difference between Q5 and Q6 Modifier
The Q5 and Q6 modifiers are closely related and prone to confusion. Here’s the difference between them:
| Q5 Modifier | Q6 Modifier | |
|---|---|---|
| Official Description | Services provided by a substitute physician under a reciprocal billing arrangement. | Services furnished under a fee-for-time compensation arrangement by a substitute physician/ |
| Type of Arrangement | Reciprocal billing (colleague covering colleague). | Locum tenens (temporary hired substitute). |
| Provider Relationship | Both physicians must be enrolled in Medicare and typically know each other professionally. | Locum tenens is an independent contractor hired on a per diem or hourly basis. |
| Payment to Substitute | No money exchanged between physicians because the arrangement is informal and mutual. | The substitute is paid on a per diem or fee-for-time basis by the regular physician or employing facility. |
| Has Own Practice? | Yes. The covering physician has their own practice and patient panel. | No. The locum tenens typically do not have their own patient panel or an independent practice. |
| Max Billing Period | Up to 60 continuous days (same as Q6). | Up to 60 continuous days (exception for active military duty). |
| Claim Form Field | Box 24D of CMS-1500 | Box 24D of CMS-1500 |
Conclusion
Let’s wrap up everything we have discussed in this guide.
- The Q6 modifier is used to bill Medicare for services delivered by a locum tenens physician in the temporary absence of a regular physician.
- This temporary physician is paid using a fee-for-time payment model.
- Q6 billing is limited to a maximum of 60 continuous days, after which the locum tenens must bill independently.
- It is used only for physicians. You cannot use it for non-physician practitioners like CRNAs, NPs, and PAs.
If your practice regularly hires substitute physicians, partnering with billing experts is the best and safest way to guarantee your payments. You should outsource medical billing services to specialized companies like MediBillMD for the best results.
