Provider Enrollment / Credential OS

Never miss the date that quietly stops your billing.

Here is the short answer. Medicare revalidation is not a warning, it is a switch. When a provider's PECOS revalidation due date passes without a filed CMS-855, the Medicare Administrative Contractor can deactivate billing privileges under 42 CFR 424.540. Claims for dates of service inside that gap reject, and the 30-day retrospective billing window in 42 CFR 424.521 will not stretch across a month you never saw coming. Credential OS tracks every provider's due date and effective date so the lapse is caught before the switch flips.

5 yrstandard revalidation cycle, 42 CFR 424.515

3 yrDMEPOS suppliers, 42 CFR 424.57

30 dretrospective billing limit, 424.521

The lifecycle, one date at a time

Where a Medicare enrollment silently goes cold

A revalidation is a clock that starts the day an enrollment is approved and runs quietly in the background for years. The failure is almost never dramatic. It is a due date nobody was watching. Follow the vertical timeline below to see exactly where the money leaks, and where Credential OS puts a stop on it.

Day 0 / Approval

The clock starts, and so does the effective date

The MAC approves the CMS-855 and sets the effective date of billing privileges under 42 CFR 424.520(d). That same approval quietly starts a five-year revalidation clock, three years for DMEPOS suppliers. Nobody circles the return date.

42 CFR 424.515 · 424.520(d)

Years 1 to 4 / Drift

Reality moves, PECOS does not

Providers change practice locations, groups add sites, and reassignments shift on CMS-855R. Every change is a data point PECOS expects to match at revalidation. Left untracked, small drift becomes a stack of corrections due all at once.

CMS-855B · CMS-855I · CMS-855R

T minus 90 days / Notice

The due date is published, not always delivered

The MAC posts the revalidation due date on the CMS Revalidation Due Date Lookup Tool and mails a notice inside the 90 day window. Mail goes to the address of record. If that address is stale, the only warning you get is the one you never open.

CMS Revalidation Due Date Lookup Tool, data.cms.gov

The due date / Action

File a complete CMS-855 revalidation

The provider submits a full revalidation through internet-based PECOS or on the paper CMS-855A, 855B, 855I, 855O, or 855S. Incomplete responses restart the review and eat the runway you had left before the switch flips.

Medicare Program Integrity Manual, Pub. 100-08, Ch. 15

Missed / Deactivation

Billing privileges deactivate

Miss the date and the MAC may deactivate the enrollment under 42 CFR 424.540. This is not a denial you can appeal line by line. It is an off switch. Every claim tied to that PTAN and NPI now has a problem the front desk cannot see.

42 CFR 424.540 · 424.545

The silent gap / Loss

A month of claims turns unbillable

Reactivation does not reach back cleanly. The reactivation effective date, paired with the 30 day retrospective billing limit in 42 CFR 424.521, leaves a window of dates of service that Medicare will not pay. The care happened. The claims are simply stranded.

42 CFR 424.521 · 424.540(b)

With Credential OS / Prevention

The date is tracked before it can bite

Credential OS holds every provider's revalidation due date and effective date as structured data, not as a letter in a pile. Alerts fire well ahead of the window, so the CMS-855 goes in on time and the enrollment never quietly goes cold.

Credential OS enrollment tracking layer

Know the form, know the trigger

The CMS-855 family Credential OS keeps current

Revalidation is not one form. It is the right form for the right enrollment, filed against a moving due date. Credential OS maps each provider and entity to its correct 855 so nothing is filed on the wrong track.

855IIndividual physicians and non-physician practitioners

855BClinics, group practices, and other supplier organizations

855AInstitutional providers billing Part A

855RReassignment of Medicare benefits to a group

855OOrdering and referring only, no billing privileges

855SDMEPOS suppliers, on the shorter three-year cycle

Why the gap is unforgiving

The effective date does not stretch to cover you

Where the unbillable window lives

Under 42 CFR 424.521, physicians and practitioners may bill retrospectively for services up to 30 days before the effective date. That window is a courtesy, not a safety net. When a deactivation runs longer than 30 days, the dark stretch between the last good date and the reactivation date is revenue Medicare will not pay.

Enrolled and billing Deactivated, unbillable Reactivated

◀ on-time revalidation keeps this green 30-day look-back cannot cover a long gap ▶

Two ways to run enrollment

A pile of letters, or a tracked date

Untracked Spreadsheet and hope

Due dates live in a MAC letter, if it reaches the right desk
Reassignments and address changes drift out of sync in PECOS
Nobody owns the date, so nobody watches the clock
The lapse surfaces as rejected claims weeks later
Recovery means reactivation plus a written-off gap

Credential OS Date as data

Every revalidation due date stored and monitored per provider
Effective dates tracked so retrospective billing is used well
Alerts fire ahead of the 90-day window, not after the switch
Each provider mapped to the correct CMS-855 form
A lapsed enrollment never silently turns a month unbillable

Guidelines cited

42 CFR 424.515, revalidation of enrollment information, standard five-year cycle
42 CFR 424.520(d) and 424.521, effective date of billing privileges and the 30-day retrospective billing limit
42 CFR 424.540 and 424.545, deactivation of billing privileges and provider rights
42 CFR 424.57, DMEPOS supplier standards and the three-year revalidation cycle
CMS-855A, 855B, 855I, 855O, 855R, and 855S Medicare enrollment applications
CMS Revalidation Due Date Lookup Tool, data.cms.gov, Medicare Provider Enrollment
Medicare Program Integrity Manual, Pub. 100-08, Chapter 15, provider enrollment
CY2026 Medicare Physician Fee Schedule Final Rule, 42 CFR Part 424 Subpart P

See your revalidation calendar before Medicare does

Credential OS turns every provider's PECOS due date and effective date into tracked, alerting data, so a missed revalidation never quietly costs you a month of billable care. Let us map your roster to its due dates and show you where the next lapse would have landed.

Book a Credential OS enrollment review

ASP-RCM Solutions · Senior Partner · Frisco