Billing Under Another Physician: What Actually Holds Up

Key Finding: Billing under another physician is legal, but only in narrow cases. Reciprocal billing and locum tenens cover an absent doctor for up to 60 days. Neither one lets you bill a new hire who is not yet credentialed. That shortcut is a compliance risk, not a solution. This guide shows what actually holds up.

Your new physician started Monday, and the claims are already piling up. Someone suggests billing under another physician until credentialing clears. It feels harmless, and everyone seems to do it. Billing under another physician is fine in a few narrow situations. This is not one of them. A new, not-yet-credentialed hire is not a locum tenens. Get it wrong, and a credentialing gap turns into a compliance problem. The revenue pressure is real. That shortcut just moves the risk somewhere worse.

A note on scope. Credentialing and enrollment decisions rest with the payer and your practice. A credentialing partner like HRG supports the surrounding workflow. That work covers the enrollment application, reassignment, payer follow-up, and correct claim submission. Your practice retains authority over decisions that require its direct attestation.

What billing under another physician actually means

Billing under another physician has one legitimate purpose. It covers a regular physician who is temporarily absent. The patient came for your doctor, who is out sick or on leave. A substitute steps in, and the practice still bills correctly. Medicare allows this through two specific arrangements. It does not allow it for a brand-new provider. That distinction is where practices get into trouble.

Reciprocal billing and locum tenens, the paths that hold up

Two Medicare arrangements make billing under another physician legitimate. Reciprocal billing uses modifier Q5. Two physicians informally cover for each other. Fee-for-time, still called locum tenens, uses modifier Q6. The regular physician pays a substitute per day. Both share the same guardrails. The regular physician must be absent. A substitute covers no more than 60 continuous days. Your regular doctor still bills under their own NPI with the modifier. CMS sets these substitute billing rules in its claims processing manual. Noridian lays out the reciprocal billing and locum tenens rules clearly.

Where practices get billing under another physician wrong

The trouble starts with a new hire. A practice bills the new doctor's visits under a credentialed colleague. They call it locum tenens, but it is not. Locum tenens covers an absent regular physician, not a permanent new provider. The new hire has no absence to cover. That claim misrepresents who rendered the service. Payers audit for exactly this pattern. The penalties dwarf the delayed revenue you were chasing. Getting the provider properly credentialed is the fix, not faking the claim.

90 to 120 days: the manual credentialing wait that tempts the shortcut in the first place.

What actually holds up for a new, not-yet-credentialed provider

A new hire's claims still need a safe home. You protect them without breaking the rules. Start the enrollment the day you hire, not the day they start. Ask each payer for a retroactive effective date tied to the start. Hold the claims until the provider is linked and enrolled. Then bill them correctly under the new provider's own NPI. That path is slower, but it survives an audit. The shortcut does not.

How HRG handles billing under another physician

Here is HRG's lane. HRG keeps new-provider enrollment moving so the shortcut is never needed. It files the enrollment early and pursues retroactive effective dates. HRG applies Q5 and Q6 correctly when a real substitution happens. The team audits and verifies coding accuracy, but does not perform your coding. Your coders own the coding itself. The team holds and releases claims so nothing bills under the wrong NPI. It works inside your existing EHR and payer portals. No separate dashboards, no PDF reports, no offshore handoffs. When a claim is at risk, HRG responds in 24 to 48 hours. Over 26 years, HRG holds a 100 percent hospital privilege approval record. U.S.-based staff run the enrollment, not an offshore queue. So a new hire bills clean, without the compliance gamble. That is what the right credentialing support looks like.

If a new hire's claims are tempting you toward the shortcut, there is a safer path. Getting them enrolled and billable is exactly what HRG does. Talk through your pending providers with Mellissa Harmon before the claims age out. Book a credentialing review with Mellissa. No pitch, no contract pressure.

Billing under another physician questions practices ask

Can we bill a new physician under another doctor while credentialing is pending?

No. Billing under another physician is for covering an absent regular doctor. A new hire is not a substitute, so it does not qualify. HRG holds those claims and pursues retroactive enrollment instead.

What is the difference between Q5 and Q6?

Q5 is reciprocal billing, an informal cover between two physicians. Q6 is fee-for-time, still called locum tenens, with a paid substitute. Both require an absent regular physician and a 60-day limit. HRG applies the right modifier when a real substitution happens.

How long can a substitute physician bill under the regular NPI?

Up to 60 continuous days, then no longer. After that, the substitute must bill under their own NPI. The clock runs on calendar days, not days worked. HRG tracks the 60-day window so you do not cross it.

What should we do with a new hire's claims meanwhile?

Hold them until the provider is enrolled and linked. Pursue a retroactive effective date tied to the start. Bill them under the new provider's own NPI once active. HRG manages that hold, the enrollment, and the release.

Does HRG code these claims for us?

No. HRG audits and verifies coding accuracy against the record. Your coders keep ownership of the coding. HRG applies the correct billing modifier and manages the claim.

Is billing under another physician ever worth the risk?

No, not for an uncredentialed new hire. The audit exposure far outweighs a few weeks of delayed revenue. Proper enrollment recovers that revenue without the risk. HRG gets the provider billable the compliant way.

The narrow place it holds up

Billing under another physician has a real, narrow place. Covering an absent doctor with Q5 or Q6 holds up. Billing a new, uncredentialed hire under a colleague does not. Fix the enrollment fast, and the shortcut loses its appeal. See how HRG approaches provider credentialing.