Glossary · Compliance

CERT (Comprehensive Error Rate Testing)

CERT (Comprehensive Error Rate Testing) is the CMS program that annually measures the Medicare fee-for-service improper payment rate by auditing a statistically valid random sample of processed claims against coverage, coding, and billing rules. It does not identify fraud—it identifies payments that failed to meet Medicare requirements.

Verified May 8, 2026 · 8 sources ↓

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Definition

Source · Editorial summary grounded in 8 cited references ↓

The Centers for Medicare & Medicaid Services launched CERT to produce a defensible, statistically valid estimate of how often Medicare fee-for-service claims are paid incorrectly. Each year, an independent CERT Review Contractor pulls a stratified random sample of processed claims—37,500 claims starting with Reporting Year 2025, down from 50,000—and requests supporting medical records from the billing provider or supplier. Reviewers then determine whether each claim satisfied Medicare's coverage criteria, coding rules, and billing requirements. The FY 2025 estimated improper payment rate was 6.55 percent, representing roughly $28.83 billion. That rate feeds published contractor-level and service-specific error reports that Medicare Administrative Contractors (MACs) use to target provider education.

For orthopedic practices, CERT scrutiny is most acute when documentation does not clearly support the procedure billed. The most common error categories include insufficient documentation (the record exists but does not justify the code submitted), no documentation (records never reached the reviewer within the 75-day window), and incorrect coding (the submitted CPT or ICD-10 code does not match what the clinical record describes). A CERT error does not automatically become a recoupment, but a MAC may adjust or reverse payment once the review is complete.

CERT findings also shape Local Coverage Determinations and MAC educational bulletins, meaning aggregate errors in orthopedic service categories—spinal injections, joint replacements, durable medical equipment—can trigger heightened prepayment or post-payment scrutiny across an entire specialty. Practices that receive a CERT medical record request should respond through the CERT C3HUB portal, confirm the documentation matches the billed service exactly, and track review status within the 120-day completion window before considering a redetermination appeal.

Why it matters

If your claim is selected and you fail to submit records within 75 days, CERT automatically classifies it as a 'no documentation' error and your MAC may reverse payment with no further review of the underlying service—even if the care was entirely appropriate. Beyond individual claims, orthopedic service categories that accumulate high CERT error rates attract MAC medical review initiatives, pre-authorization requirements, and targeted audits that increase administrative burden practice-wide.

Common mistakes

Where people most often go wrong with this concept.

Source · Editorial brief grounded in cited references ↓

Responding to the CERT record request after the 75-day deadline, triggering an automatic no-documentation error even when the clinical record is complete and accurate.
Sending records to the MAC instead of directly to the CERT Documentation Center or via the C3HUB portal, causing delays that count against the response window.
Submitting an operative report alone for musculoskeletal procedures without including the pre-operative evaluation, imaging interpretation, or post-op notes that establish medical necessity.
Billing a higher-complexity E/M or procedure code than the documented record supports, the most common 'insufficient documentation' error in orthopedic audits.
Assuming a CERT error letter is the same as a fraud referral and not responding, rather than treating it as a documentation compliance issue that can be corrected or appealed.
Failing to monitor claim status on the CERT C3HUB after submitting records, missing the opportunity to identify and appeal an adverse review decision within the redetermination window.
Confusing CERT with RAC (Recovery Audit Contractor) audits—CERT is a measurement program that estimates error rates; RAC audits are recovery-focused and use different sampling and appeal rules.

Related codes

Codes commonly involved when this concept appears in practice.

CPT

ICD-10

M17.11 M16.11

Modifiers

59 Distinct procedural service 25 Significant separately identifiable E/M KX Medical-policy requirements met LT Left side RT Right side

Frequently asked questions

Source · Generated from the editorial pipeline, verified against 8 cited references ↓

01Does a CERT error mean my practice is under investigation for fraud?

No. CMS explicitly states that CERT error rates measure payments that did not meet Medicare requirements—they do not indicate fraud. A CERT error is a documentation or coding compliance finding, not a referral to law enforcement.

02How are claims selected for CERT review?

The CERT Review Contractor uses a stratified random sample of Medicare FFS claims already processed by MACs. Selection is random; it is not triggered by prior audits, complaint history, or billing volume at your practice.

03What happens if I miss the 75-day documentation submission deadline?

The claim is categorized as a 'no documentation' error regardless of whether the underlying service was appropriate. Your MAC may then adjust or reverse the payment. Records submitted after 75 days may still be reviewed for data-gathering purposes but will not reverse the no-documentation classification.

04How do I find out whether my specific claim was flagged as an error?

Log in to the CERT C3HUB at c3hub.certrc.cms.gov to check claim review and documentation status. The portal is updated daily by the CERT contractor.

05Can I appeal a CERT error determination?

Yes. Once your MAC adjusts the claim based on the CERT finding, you may follow the standard Medicare redetermination process. The appeal is filed with your MAC, not with the CERT contractor.

06Why did CMS reduce the CERT sample size starting in Reporting Year 2025?

CMS permanently reduced the annual sample from 50,000 to 37,500 claims beginning with RY 2025. The change reflects a programmatic decision to maintain statistically valid national and contractor-level error rate estimates at lower administrative cost; it does not reduce the likelihood that any individual high-volume service will be sampled.

07Which orthopedic services have historically drawn high CERT error rates?

Spinal procedures, joint injections, durable medical equipment (bracing, orthotics), and evaluation and management services billed with same-day procedures have consistently appeared in MAC CERT error reports. Insufficient documentation of medical necessity is the most frequently cited deficiency across these categories.

Sources & references

Editorial content was developed using the following public sources. Last verified May 8, 2026.

Mira AI Scribe

CERT Compliance Flag — Documentation Sufficiency Check When Mira detects a service category with elevated CERT error history (e.g., spinal injections, total joint replacement, shoulder arthroscopy, fracture management), apply the following documentation layer before the note is finalized: 1. MEDICAL NECESSITY ANCHOR: Confirm the note explicitly states the diagnosis, failed conservative treatment duration and type, and functional limitation. Vague phrases like 'patient has knee pain' are insufficient. Write: 'Patient has right knee medial compartment osteoarthritis (M17.11) with 6 months of failed PT and NSAIDs; functional limitation prevents ambulation >1 block.' 2. CPT-TO-RECORD MATCH: Verify the operative or procedure note describes every component of the billed CPT code. If billing 29827 (shoulder arthroscopy with rotator cuff repair), the note must document visualization, the tear, repair technique, and materials. Partial documentation supporting only debridement (29823) is a common CERT downcode trigger. 3. MODIFIER JUSTIFICATION: When modifiers 59, LT/RT, or 25 are applied, the note must contain an independent rationale. CERT reviewers flag modifier use unsupported by distinct clinical content. 4. RESPONSE READINESS: Flag that if this claim is selected for CERT review, records must be submitted within 75 days to avoid automatic no-documentation error. Ensure the PECOS correspondence address is current so the Medical Record Request Letter reaches the correct location. Mira will surface this checklist in the documentation review panel for any note attached to a CPT code appearing in the prior three years of MAC CERT error reports.

See Mira's approach

Related terms

Post-payment review Compliance

A post-payment review is a payer's retrospective examination of already-paid claims to verify that billed services were medically necessary, properly documented, and correctly coded—and to recover funds when they were not.

Redetermination (Medicare appeal level 1) Billing

A redetermination is the first of five Medicare appeal levels, in which a Medicare Administrative Contractor (MAC) conducts a fresh review of a denied or partially paid claim; the request must be filed within 120 days of receiving the initial determination notice.