What is CERT?

Comprehensive Error Rate Testing (CERT) is a CMS program that measures Medicare Fee-for-Service improper payment rates by auditing randomly selected claims for compliance with coverage, coding, and documentation requirements. For wound care providers, CERT findings on insufficient documentation and medical necessity can signal areas of heightened scrutiny and increased audit risk. 

Key Takeaways 

• CERT is a measurement program, not a targeted investigation—but its findings shape payer education and future audit focus.  
• Missing/insufficient documentation is a major error driver and can be counted as an improper payment even when care was appropriate clinically.  
• CTP/skin substitute claims are audit-sensitive due to coverage rules and spend, so strong episode-level documentation is essential.  

CERT stands for Comprehensive Error Rate Testing—a Centers for Medicare & Medicaid Services (CMS) program used to estimate the Medicare Fee-for-Service (FFS) improper payment rate. Each year, CERT contractors review a statistically valid, stratified random sample of processed Medicare FFS claims to determine whether they were paid correctly under coverage, coding, and billing rules.1 

How CERT Works in Practical Terms 

When a claim is selected, CMS (through CERT contractors) requests records from the billing provider. Reviewers assess whether the documentation supports what was billed and whether Medicare requirements were met. If the claim fails coverage/coding/payment rules—or if records aren’t submitted—it may be counted as a total or partial improper payment.2 

CERT also categorizes why errors occur. One of the most important categories for clinicians is insufficient documentation—meaning the submitted record is not adequate for the reviewer to conclude the services were provided as billed and/or were medically necessary, or that required elements (such as certain signatures/orders) are present.3 

Why Wound Care Teams Should Care—Especially for Skin Substitutes 

Wound care claims can be complex, longitudinal, and documentation-heavy. That risk increases with cellular and tissue-based products (CTPs)/skin substitutes, where Medicare coverage is often tightly linked to ulcer type, prior conservative therapy, product use parameters, and medical necessity as reflected in the record and applicable coverage policies.4 

While CERT itself is not a fraud program, its national findings inform Medicare Administrative Contractor (MAC) education and process improvements—and, in the real world, documentation patterns identified through improper payment measurement can overlap with areas that later see heightened review across Medicare integrity activities.5 

References 

1. Centers for Medicare & Medicaid Services. Comprehensive Error Rate Testing (CERT) Program. CMS. Updated 2026. Accessed March 2026. https://www.cms.gov/data-research/monitoring-programs/improper-payment-measurement-programs/comprehensive-error-rate-testing-cert?  
2. Centers for Medicare & Medicaid Services. What’s the Comprehensive Error Rate Testing (CERT) Program? CMS. Published 2022. Accessed March 2026. https://www.cms.gov/outreach-and-educationmedicare-learning-network-mlnmlnproductsfast-facts/whats-comprehensive-error-rate-testing-cert-program?  
3. Centers for Medicare & Medicaid Services. CERT Assignment of Error Categories: January 2016. CMS. Published January 2016. Accessed March 2026. https://www.cms.gov/Research-Statistics-Data-and-Systems/Monitoring-Programs/Medicare-FFS-Compliance-Programs/CERT/Downloads/CERTAssignmentofErrorCategories_January2016.pdf?  
4. Office of Inspector General, US Department of Health & Human Services. Medicare Part B Payments for Skin Substitutes. OIG. Accessed March 2026. https://oig.hhs.gov/reports/work-plan/browse-work-plan-projects/medicare-part-b-payments-for-skin-substitutes/?  
5. Novitas Solutions. Comprehensive Error Rate Testing (CERT) Insider’s Guide. Novitas Solutions. Accessed March 2026. https://www.novitas-solutions.com/webcenter/portal/MedicareJL/pagebyid?contentId=00094213&