Locum tenens credentialing: privileging, payer billing, and the Q6 modifier

Locum tenens credentialing has its own rulebook — different from permanent-staff credentialing, different from telehealth, and full of small federal-vs-payer nuances that catch new MSP teams off guard. This guide covers temporary privileging, payer reciprocity, the Medicare Q6 modifier (and its successor "fee-for-time" terminology), the 60-day rule, and how to keep the file audit-ready when a provider is only on site for two weeks.

What "locum tenens" actually means

Strictly, locum tenens is a temporary physician (or APP) filling in for a regular practitioner who is absent. CMS treats locum tenens as an independent contractor of the regular practitioner, not of the practice — that is the legal foundation that makes the special billing rules work.

In day-to-day usage the term is also used loosely for any short-term substitute. The billing rules below only apply when the relationship meets the strict CMS definition; otherwise the locum has to enroll and bill under their own NPI like any other provider.

Temporary privileging at the facility

The Joint Commission (MS.06.01.13) and CMS Conditions of Participation both allow hospitals to grant temporary privileges to a locum in two situations:

1. Important patient care need — for example, the regular practitioner is on leave and patients need coverage. Limited to short durations and must be tied to a specific need.
2. Pending complete application — the locum has submitted a full medical-staff application that is in process. Privileges can be granted for up to 120 days while the application completes.

Either pathway still requires verification of current license, DEA (if prescribing), NPDB query, OIG/SAM exclusion check, malpractice history, and competence in the privileges requested. Temporary privileging compresses the timeline; it does not waive the substance.

Payer credentialing reciprocity

Most commercial payers will not credential a locum on an expedited basis — the standard 90–180 day payer enrollment timeline applies. For short locum coverage this would make billing impossible if you had to wait for full credentialing.

Three real-world workarounds:

• Bill under the absent provider's contract using the Medicare Q6 modifier (see below). Each payer has its own version of this allowance; confirm in the payer contract.
• Use a locum agency's existing payer roster. Some agencies pre-credential their locums with major payers; the practice contracts with the agency rather than the individual.
• Use a CVO that holds delegated credentialing with your payer mix. Delegated credentialing can move credentialing turnaround inside 30 days for a locum that is already on file.

The Medicare Q6 modifier and the 60-day rule

Medicare's locum tenens billing rules, originally written for physicians, were broadened by Section 16006 of the 21st Century Cures Act and updated in CMS guidance to use the term "fee-for-time compensation arrangements". The substance is the same as the older locum tenens billing rule.

The mechanics:

• The regular practitioner is unavailable.
• A substitute (the locum) sees the patient.
• The claim is billed under the regular practitioner's NPI with modifier Q6 appended to the procedure code to indicate the service was performed by a substitute.
• The substitute is paid by the regular practitioner (or the practice) on a per-diem or fee-for-time basis — not as an employee, not as a billing provider.

The famous 60-day rule: under the original locum regulations, the regular practitioner could bill under Q6 for a continuous period not to exceed 60 continuous days per coverage event. If the regular practitioner is out longer — military service, certain other statutorily defined absences are exempt — the locum must enroll and bill under their own NPI. The 60-day cap continues to apply under the fee-for-time arrangement language; see the current CMS guidance on locum tenens and fee-for-time arrangements for the live rule.

Worth flagging: the 60-day clock is a continuous-coverage clock, not a calendar-quarter clock. A locum filling in for the same physician for 61 consecutive days breaks the rule even if it crosses a month boundary.

HQ7 for physical therapists

The same Section 16006 created an HQ7 modifier for PT fee-for-time arrangements in Health Professional Shortage Areas (HPSAs), medically underserved areas, or rural areas. The structure mirrors Q6 but applies only in those settings. If you bill PT services through a locum-equivalent arrangement, know whether your geography qualifies before you use HQ7.

What the locum file needs to contain

Even a two-week locum needs a primary-source-verified file. At minimum:

• Current state medical license (and CSR / DEA if prescribing) for the state of service.
• Recent NPDB query — see NPDB queries for credentialing for how to handle this efficiently for short engagements.
• OIG LEIE and SAM.gov exclusion screening — covered in OIG and SAM.gov exclusion verification.
• Board certification verification — see board certification verification.
• Current malpractice coverage with the practice listed as additional insured, or coverage from the agency.
• A copy of the locum agreement showing the fee-for-time / Q6 relationship to the regular practitioner.
• Re-attested CAQH ProView profile inside the 120-day window, even for short engagements, so any payer that pulls during the locum period gets current data.

Common mistakes

• Treating the 60 days as 60 business days. It is 60 continuous calendar days.
• Billing Q6 when the regular practitioner has resigned. Q6 is for absence, not vacancy. If the regular provider has left the practice, the substitute must bill under their own NPI from the first day.
• Skipping the NPDB and OIG checks because "it's only two weeks." Exclusion and adverse-action liability does not shorten with the engagement.
• Missing the locum's state CSR. A locum coming from out of state needs the destination state's controlled-substance registration before prescribing — covered in DEA registration renewal.

Where this fits

Locum credentialing is the place where every other credentialing sub-process gets tested against a tight clock. The teams that handle it well treat the locum file as a standard credentialing file with a compressed turnaround, not as a shortcut.

CredentialTrack Pro supports locum-specific workflows — short-term engagements with their own expiration dates, agency relationships, and per-state license stacks — alongside the rest of the roster. See CredentialTrack for credentialing coordinators or our pricing.