The Most-Billed and Most Error-Prone CPT Codes of 2023

As the calendar turns to 2024, it’s a good time to take stock of appropriate medical coding practices, which for some primary care providers means evaluating coding trends. As most practices know, auditors sometimes look for providers who fall outside of the Medicare averages when determining whether a practice may be coding inappropriately. And, while some clinicians very legitimately report codes outside the norm, it can still be a good idea to check in on where other practices stand as a benchmark.

To get a handle on those details, we’ve provided a look at the most frequently reported evaluation and management (E/M) codes, as well as the most common coding errors, of 2023. This roundup is based on the US Department of Health and Human Services’ recently released report, 2023 Medicare Fee-for-Service Supplemental Improper Payment Data.

Most-Billed Office Visit Code: 99214

The most recent Centers for Medicare & Medicaid Services (CMS) utilization data (from FY 2022) indicate that Medicare Part B paid for more instances of 99214 (Office or other outpatient visit for the evaluation and management of an established patient, which requires a medically appropriate history and/or examination and moderate level of medical decision making. When using total time on the date of the encounter for code selection, 30 minutes must be met or exceeded) than any other outpatient office visit codes.

Medicare allowed 98.5 million claims for 99214 in 2022, with 99213 not far behind at 73.6 million paid claims.

Among new patient office visits, the code 99204 (Office or other outpatient visit for the evaluation and management of a new patient, which requires a medically appropriate history and/or examination and moderate level of medical decision making. When using total time on the date of the encounter for code selection, 45 minutes must be met or exceeded) was the most frequently billed.

Medicare allowed 12.3 million claims for 99204 in 2022, with 99203 coming in second at 9.6 million claims.

Because 2022 was only the second year that providers were able to use the newer E/M guidelines (coding based on time or medical decision-making, rather than the previous method of using history, exam, and medical decision-making), primary care clinicians may wonder whether this utilization data differs from the time when the previous guidelines were in place.

However, a review of Medicare data from 2013 reveals that the code utilization has remained fairly consistent since that time, when 99214 was reported more often than 99213, and the use of 99204 topped the level-three code, 99203.

Keep in mind that some practices are completely justified in having a different billing pattern than Medicare averages. For instance, a primary care physician who only sees patients with chronic illnesses and multiple diagnoses might report more level-five codes than average, while a physician who sees mainly healthy patients may submit more claims with level-two and level-three codes than average.

The key is to ensure that every code reported is justifiable by thorough and accurate documentation.

Higher-than-Average Error Rate for Primary Care

When CMS analyzed the most frequent Part B Medicare errors, it found that primary care practices logged relatively high error rates compared to the average.

To help create the 2023 improper payment data report, CMS reviewed 45,310 claims with dates of service spanning from July 1, 2021, through June 30, 2022. Auditors reviewed the claims to evaluate which were billed properly and which had errors. Part B errors reflect issues that occurred when providers saw patients in the office setting, while Part A claims cover patients in the inpatient setting, such as hospitals.

The report indicates that the average Part B error rate among all provider types was 10.0%. Family practice providers, however, had a 13.8% error rate, while internal medicine providers logged a 12.9% error rate. In fact, because of the high volume of internal medicine claims, these specialists were responsible for 3.2% of all improper Part B payments, topped only by clinical laboratories, which comprised 3.4% of all improper payments.

To be clear, however, primary care providers were not the biggest offenders when it came to problematic Part B claims. Chiropractors logged a 39% error rate, pulmonologists logged a 32% error rate, and portable x-ray suppliers had a 47% error rate.

Office Visits, Lab Tests Led Part B Errors

While the Comprehensive Error Rate Testing (CERT) report does not break down the specific errors that CMS discovered by specialty, the agency does share data about the claim types that were responsible for the highest volume of Part B errors, and all three of the top errors are services that primary care providers tend to bill quite frequently.

Last year’s CERT report showed that lab tests were the most-error prone Part B services, but that was not the case in 2023, when established patient office visits were responsible for the most Part B errors. Lab tests came in second place, with minor procedures coming in third.

Established Patient Office Visits

Among E/M visits for established patients (99211-99215), most errors were due to incorrect coding, while insufficient documentation errors came in second place.

When it comes to office visit coding, there are several issues that can cause incorrect coding errors, but it typically means the provider reported a code that was higher or lower than what the documentation supported. For instance, the provider documents 20 minutes with an established patient with diabetes and reports 99215. Because 99215 requires at least 40 minutes of total time, the payer would downcode this claim to 99213 and log it as an incorrect coding error.

Laboratory Tests

The vast majority of lab tests were marked as errors by Part B reviewers due to insufficient documentation, with a missing ‘provider intent to order’ leading the list of issues. Also problematic were missing documentation to support medical necessity, an inadequate order, or a missing risk assessment for urine drug screen, CMS noted.

Minor Procedures

Minor procedures under Medicare comprise everything from injections to therapy, and beyond. CMS flagged missing documentation for physical, occupational, or speech therapy as the biggest issue in this category, followed by incorrect coding for units of service and unsigned documentation.

Keep in mind that all minor procedures must be justified with documentation, and when it comes to therapy services, the provider must certify or recertify the patient and retain those records and orders for the appropriate length of time required by state law.

Florida, California Responsible for Highest Volume of Errors

When CMS broke down Medicare errors by state, the agency noted that Florida providers were responsible for 10.8% of all improper payments, followed by California, Texas, Pennsylvania, and New York. This may make sense since these states submitted a high volume of services to Medicare. However, when it came to the actual per-state error rate, West Virginia providers logged the highest rate of errors with a 23.6% improper payment rate.

Providers seeking to evaluate whether they are making any errors should perform regular self-audits to confirm that all services they report are accurate and justified, with thorough documentation to support all claims.