The Medicare Part B improper payment rate for fiscal year 2025 is 8.4%, according to the Centers for Medicare & Medicaid Services (CMS). That equals $9.6 billion of $114.1 billion in Part B payments, with a 95% confidence interval of 7.6% to 9.3%.
CMS measures the rate through its CERT program. For the 2025 report, reviewers sampled 11,920 Part B claims and completed review of 11,600 of them. The claims were submitted from July 1, 2023 through June 30, 2024. The national Medicare fee-for-service rate across all claim types is 6.55%, or $28.83 billion, per the American Health Care Association summary of the CMS data. Part B makes up 33.4% of all improper payments. Across every claim type, CMS sampled 49,061 claims and reviewed 37,651 against $439.9 billion in total payments.
Where the 8.4% Comes From
CMS sorts each Part B error by what the reviewer found in the records. Insufficient documentation is the largest group by far, at 58.4% of Part B improper payments. Applied to the $9.6 billion total, that is about $5.6 billion. The CMS sample covers Medicare fee-for-service claims only, so the rates do not describe commercial payers.
Incorrect coding follows at 18.8%. No documentation, meaning the provider did not respond to the records request, accounts for 15.7%. Other errors make up 5.5%, and medical necessity errors are 1.6%.
Other claim types look different. CMS reports 3.1% for hospital inpatient claims (Part A, IPPS) and 24.1% for durable medical equipment, prosthetics, orthotics and supplies. Part A claims outside the inpatient system, such as skilled nursing, run 6.7%.
The Highest-Dollar Part B Services
The table lists the six Part B service types with the most projected improper dollars in the CMS report. Rates vary widely, and most of the leading categories are documentation problems.
| Service type | Projected improper payments | Improper payment rate | Largest error type |
|---|---|---|---|
| Lab tests, other (non-Medicare fee schedule) | $1.36 billion | 27.9% | Insufficient documentation, 79.9% |
| Minor procedures, other (Medicare fee schedule) | $991.4 million | 17.6% | Insufficient documentation, 77.6% |
| Office visits, established | $853.7 million | 5.3% | Incorrect coding, 65.2% |
| Hospital visit, subsequent | $703.0 million | 13.8% | Incorrect coding, 51.4% |
| Specialist, other | $675.5 million | 25.0% | Insufficient documentation, 84.0% |
| Ambulance | $452.6 million | 10.4% | Insufficient documentation, 46.7% |
Source: CMS, 2025 Medicare Fee-for-Service Supplemental Improper Payment Data, Table D1.
Established office visits rank third in dollars but have a low rate, 5.3%. New office visits run higher at 7.6%, or $229.7 million, and 77.6% of that amount is incorrect coding.
Office Visit Coding Errors
For established office visits, CMS attributes 65.2% of improper dollars to incorrect coding. Another 18.4% is no documentation and 16.4% is insufficient documentation.
Two codes carry most of the weight. Code 99214 has $459.8 million in improper payments at a 5.0% rate. Code 99215 has $245.2 million at 14.8%. The low-level visit, 99213, runs 2.1% on $101.3 million.
CMS also reports how many errors were off by exactly one E&M level. Across all E&M codes, those one-level differences total $1.37 billion, or 1.2% of payments. For 99215 the one-level rate is 8.7% ($144.4 million). For 99214 it is 2.6% ($238.8 million).
The CMS upcoding table, which counts services billed at a higher level than the record supports, shows $1.55 billion across Part B at a 1.4% rate. Established office visits account for $489.7 million of that, a 3.1% rate.
Error Rates by Specialty
CMS breaks down established office visit errors by provider type. The overall rate is 5.3% across 1,026 reviewed claims.
- Family practice: 2.0% (149 claims)
- Nurse practitioners: 4.1% (126 claims)
- Cardiology: 4.8% (67 claims)
- Internal medicine: 5.7% (173 claims)
- Physician assistants: 6.0% (57 claims)
- Dermatology: 6.3% (31 claims)
- Orthopedic surgery: 14.1% (32 claims)
Internal medicine accounts for the most improper dollars in this group, $156.2 million or 18.3% of the established office visit total. Nurse practitioners follow at $66.8 million (7.8%), then family practice at $47.8 million (5.6%).
Small samples give wide intervals. The orthopedic rate has a 95% confidence interval of 1.1% to 27.1%, so the 14.1% point estimate is a rough guide. Family practice, with 149 claims, has a tighter range of 0.8% to 3.2%.
Services Where Documentation Drives the Error
Chronic care management code 99490 has a 65.2% improper payment rate on $205.4 million, and 87.7% of that amount is insufficient documentation. It is the highest rate in the CMS table of E&M-family codes.
Lab tests show the same pattern. The top root cause is missing documentation of medical necessity, found in 116 sampled claims. The missing test result follows with 70 claims, and a missing provider intent to order has 50. Chiropractic services run a 30.4% rate, with 89.5% of it insufficient documentation.
For minor procedures, 62 sampled claims lacked a therapy certification or recertification. Another 28 lacked the reason a certification was late.
What a Billing Team Can Measure
The CMS data points to a short list of checks. Track the share of 99214 and 99215 claims where the note supports the level billed. Track how many CCM claims have time logs that meet the 20-minute minimum. Track how many orders and test results sit in the chart when a records request arrives.
A 15.7% share of Part B errors comes from records requests that got no response at all. CMS counts an unanswered request as an error, so a request log with a due date addresses that share directly.
Sources
- Centers for Medicare & Medicaid Services, 2025 Medicare Fee-for-Service Supplemental Improper Payment Data, fiscal year 2025 report
- American Health Care Association, CMS Issues CERT Medicare Claims Error Rate for 2025, February 2, 2026
Talk to us
Fifteen minutes about your practice and the systems you run.