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The Credentialing Timeline Checklist
Where enrollment quietly costs a practice money — and the dates that decide whether work you have already done is billable.
Credentialing failures rarely look like failures. Nobody sends a letter saying a provider is unbillable. The claims simply deny, or the enrollment quietly deactivates, and the practice discovers months of work was never payable.
Almost all of it comes down to dates — which one governs, when the clock actually starts, and who was watching it. A provider can be fully credentialed with a payer and still have a window of services nobody can bill.
This is a checklist of the dates that decide that. It applies to a solo provider adding one payer and to a group onboarding forty at once. The volume differs; the rules don't.
1. Your effective date is not the date you were approved
This is the single most expensive misunderstanding in provider enrollment. Approval tells you the application succeeded. It does not tell you which services are billable.
For physicians and non-physician practitioners, Medicare sets the effective date of billing privileges as the later of the date of filing, or the date the supplier first began furnishing services at a new practice location. Filing late does not move the clock back to when the provider started seeing patients — it moves the billable date forward to when the paperwork arrived.
There is one narrow relief valve. Retrospective billing can reach back up to 30 days prior to the receipt of the enrollment package: if the date requested is not more than 30 days prior to receipt, the requested date becomes the Medicare effective date. During a Presidentially declared disaster that window widens — reassigners can be backdated up to 120 days from the receipt date, and all others up to 90 days.
Thirty days is the entire margin for error in normal conditions. A provider who starts seeing Medicare patients sixty days before the application is filed has thirty days of services that cannot be billed to anyone.
2. Revalidation deactivates you on a schedule, and the notice is easy to miss
Medicare requires enrolled providers to revalidate their enrollment information roughly every five years. This is not optional maintenance and it is not triggered by anything the practice does — it arrives on Medicare's calendar, not yours.
Notification is where practices lose it. Revalidation letters go to the special payments address and the correspondence address on file — addresses that are often years old, sometimes a former billing company, sometimes a suite the practice has left. Reminder emails go out roughly four months before the due date and again about six weeks prior, but only if a valid email is on file.
Miss the submission window and enrollment is deactivated, typically within 60 to 75 days after the due date. Reactivation means re-enrolling, and claims for services in the gap are rejected. A provider who has practised continuously for years becomes unbillable because a letter went to the wrong address.
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The remaining sections cover ABNs, MAC coverage variation, panel scope, genetic testing scrutiny, and order-entry validation — plus the full checklist and sources. Enter your email and the rest opens on this page.
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