Here is a story we have watched play out more than once, with the numbers rounded. A new family physician finishes residency on June 30 and starts seeing patients on August 3. The practice manager submits the Medicare 855I in mid-July, the day after the contract is signed. Three commercial applications go out the following week. On August 3 the physician sees 18 patients. By the end of August, 340. None of those visits is billable to the two largest commercial payers until late October, and one plan's effective date lands on November 1 with no retroactive coverage. Something like $60,000 of charges is either held for three months or written off.
This is the normal outcome when credentialing starts at contract signing instead of at offer acceptance. Summer is when it happens most, because summer is when new graduates start. Summer is also when the rest of the credentialing work, the revalidations and the roster audits, gets postponed because everyone is on vacation. Both problems have the same fix: treat July through September as credentialing season, with a checklist and an owner.
Here is the checklist our team runs for the practices we support.
Key takeaways
- The payer's clock starts when it receives a complete application, not when the provider starts. Commercial plans commonly take 60 to 120 days; a provider starting in August needed applications in April.
- Each payer has its own effective-date rule. Write the rule for your top ten payers on one page and give it to the scheduler, who is the person actually deciding whether an uncredentialed provider sees a patient.
- Missed Medicare revalidations deactivate billing and are not retroactive. Run every NPI through the revalidation lookup each July.
- A once-a-year roster audit against each payer's provider file catches departed providers still listed, new providers missing, and wrong addresses that become directory-accuracy problems.
1. New starters: begin at the offer, not the contract
The application clock runs from the day the payer receives a complete application. Commercial plans, in our experience, take 60 to 120 days from a clean application to an effective date, and some take longer when a credentialing committee meets monthly. Medicare through PECOS is usually faster but still measured in weeks, and Medicaid varies by state from a few weeks to several months. A provider starting August 3 needed applications submitted in April or May.
What you can start before the license is in hand: the CAQH ProView profile (create it and fill everything except the state license), the NPPES record (confirm the NPI exists and the taxonomy is right), the malpractice certificate request, the hospital privilege application, and a signed 855R reassignment ready to go the day the 855I is accepted. What you cannot skip: the state license number, the DEA registration and the malpractice face sheet, which most payers require before they will process. The practical approach is a two-stage packet: everything except those three items assembled at offer acceptance, the three items dropped in the day they arrive.
2. Understand each payer's effective-date rule
This is the part that decides whether the summer visits get paid.
| Payer type | Typical effective-date behavior | What to do |
|---|---|---|
| Medicare (PECOS) | The later of the filing date or the date the provider began furnishing services at the location; CMS allows billing for services up to 30 days before the effective date in most cases | File the 855I before the start date so the 30-day window covers the first month |
| Medicaid (varies by state) | Some states allow retroactive enrollment to the application date or earlier; others do not | Ask the state enrollment unit in writing and keep the answer |
| Commercial, delegated group agreement | Often the first of the month after committee approval; some allow the roster add date | Get the credentialing committee schedule and file two cycles ahead |
| Commercial, individual contract | Frequently no retroactive coverage at all | Hold visits or reschedule to a credentialed provider until the effective date |
| Medicare Advantage | Usually follows the commercial parent's process, but requires active Medicare enrollment first | Sequence Medicare first, then MA plans |
Write the rule for each of your top ten payers on one page and give it to the scheduler. The scheduler is the person who decides whether an uncredentialed provider sees a Blue Cross patient on day one. If the schedule template for the new provider only opens to payers with an effective date on file, the problem largely solves itself; most practice management systems can restrict a provider's template by payer, and almost nobody turns the feature on.
3. Revalidations that came due while nobody looked
Medicare revalidation comes around every five years for physicians and groups (three for DMEPOS suppliers). CMS posts due dates on its revalidation lookup tool and mails notices, but the notice goes to the correspondence address on file, which in a practice that moved or changed billing companies is often wrong. A missed revalidation deactivates the enrollment and stops payment, and reactivation is not retroactive to the deactivation date. The claims for the gap are simply lost.
Every July, pull every provider and group NPI through the revalidation lookup. Anything due before March gets started now. While you are there, confirm the correspondence and pay-to addresses and the authorized official, because the person who signed the last application may have left. A practice with twelve providers and two group enrollments has fourteen records to check; the lookup takes under an hour.
4. CAQH attestations and expirables
CAQH asks providers to re-attest every 120 days. A lapsed attestation quietly stops payers from pulling updated data, and the first symptom is usually a payer letter saying a malpractice certificate or DEA registration has expired in their file, followed a few weeks later by held claims. Run the expirables report: state license, DEA, board certification, malpractice, CLIA if you have a lab, and the CAQH attestation date. Anything expiring before December gets a calendar entry with a 60-day lead and a named person.
Board certification deserves a specific mention. Several payers now check maintenance-of-certification status at recredentialing, and a physician whose certificate lapsed in the spring because a continuing certification fee went unpaid can be terminated from a panel in the fall. The physician usually does not know. The expirables report should include it.
5. The roster audit
Once a year, request the provider roster from each of your top payers and compare it, line by line, with your own list of providers, locations and tax identification numbers. In audits we routinely find providers who left two years ago still listed (a compliance problem, and a patient who calls for an appointment with a doctor who is gone), providers who joined last year missing (a payment problem), and locations with the wrong address or a missing suite number (a directory problem that becomes a No Surprises Act problem, since directory accuracy obligations run to the plan and, by contract, back to you). Summer is the time to do this because payer provider-relations staff are also less busy and respond faster.
Fix what you find with the payer's roster change form, not a phone call, and keep the confirmation. In a January dispute over an out-of-network denial, the confirmation email from August is the evidence.
6. Locum tenens and coverage arrangements
Vacations mean locums. Medicare allows a practice to bill for a substitute physician's services under the regular physician's NPI with modifier Q6 for a continuous period of up to 60 days, with specific conditions about the arrangement and the absence. Commercial payers each have their own rule, and many have none, which means the locum must be credentialed like any other provider. Check before the first locum day, not after the first denial, and keep a log of the regular physician's absence dates, because the 60-day count is the first thing an auditor asks for.
What a summer calendar looks like
- Week of July 6: list every provider starting between now and January 31 with the status of every application. File anything missing this week.
- Week of July 13: Medicare revalidation lookup for every NPI; correct addresses and the authorized official.
- Week of July 20: CAQH expirables and attestation dates; calendar entries with owners.
- August: roster requests to the top five payers; reconcile as they arrive; submit change forms.
- September: effective-date rules on one page to the scheduler; template restrictions turned on; locum arrangements for the fall reviewed.
Questions we hear
Can the new physician see patients under a supervising physician's NPI until credentialing is done?
Not for Medicare, and not for most commercial plans. Billing one physician's services under another's number is misrepresentation unless a specific rule allows it, such as the locum tenens provisions or incident-to for non-physician staff meeting the requirements. The right answer is to schedule the new physician for payers with an effective date on file and for self-pay patients, and to give them the administrative and onboarding time the credentialing gap creates.
How much of this can we do ourselves?
All of it, if someone has the hours and the payer contacts. The work is not difficult; it is relentless, and it gets dropped the moment the person doing it also covers the front desk. The practices that struggle are the ones where credentialing is the practice manager's fourth job.
What does a delayed effective date actually cost?
Multiply the new provider's daily visit volume by the share of visits on payers without an effective date, by the average allowed amount, by the number of days of delay. A provider seeing 18 patients a day with 40 percent on two uncredentialed commercial plans at $110 a visit is losing or holding about $790 a day. Ninety days of that is over $70,000, and some of it will never be recovered.
What to do this month
- List every provider starting between now and January 31 and check that every application is already filed. If one is not, file it this week and restrict that provider's schedule to payers with an effective date.
- Run the Medicare revalidation lookup for every NPI in the group.
- Pull the CAQH expirables and attestation dates and assign a name to each item expiring before December.
- Request rosters from your top five payers.
- Give the scheduler the one-page effective-date rules. If your team does not have the hours, our credentialing and provider enrollment service runs this calendar year-round, and a short call is enough to find out where your gaps are.
