The Department of Health and Human Services’ Office of Inspector General (OIG) calculates the Medicare Fee for Service improper payment rate on an annual basis through its Comprehensive Error Rate Testing (CERT) program. OIG selects and tests roughly 50,000 claims for services each year and publishes detailed testing results. Dean Dorton has developed the following interactive tool to explore the results of the testing and provided commentary to highlight some of the trends and hotspots that have emerged from the CERT results. Healthcare leaders can use this tool to help profile their organization’s service profile and identify areas of operations that may present more risk from an inaccurate coding perspective.

Part A – Hospitals

The overall error rate for hospital services has climbed over the past two years after a slight dip in 2021. Major Hip and Knee Joint Replacements is by far the most reviewed MS-DRG code in the Part A Hospital data set and the results are concerning. In 2019, only 7.7% of hip and knee replacements were found to be in error due to a lack of medical necessity. In 2023, that percentage has grown to over 41%. 

Other findings of note include:

  • MS-DRG 057 – Degenerative Nervous System Disorders without MCC is the second most reviewed MS-DRG in the five-year period—while the main cause of the error has shifted from a lack of medical necessity in 2019 to incorrect coding in 2023.
  • MS-DRG 274 – Percutaneous Intracardiac Procedures without MCC has a high error rate (28.8% of claims versus 13.6% of claims for all codes) and has gone from a relatively low number of claims tested in 2019 to one of the top 10 most tested MS-DRG codes in 2022 and 2023. The vast majority (85.5%) of errors for Percutaneous Intracardiac Procedures without MCC are due to insufficient documentation.
  • MS-DRG 627 – Thyroid Parathyroid and Thyroglossal Procedures without CC/MCC has an overall high error rate (31.8% of claims versus 13.6% of claims for all codes), but further examination shows that both the error rate and the number of claims tested have decreased from 2019 to 2023. Most errors (94.0%) for this MS-DRG were categorized as a lack of medical necessity.

Part A – Laboratory, SNF, CORF

A wide variety of healthcare providers fall under the Part A – Non-Hospital category with the largest provider types by number of claims tested being Laboratories, Skilled Nursing Facilities (SNFs), Home Health Agencies (HHAs), and Hospices. This group of providers has the overall lowest error rate within the five-year period of 11.9%. The number of claims reviewed for laboratories has steadily increased over the five-year period, while the number of claims for SNFs, HHAs, and Hospices decreased during the pandemic while rebounding in 2023. Some highlights for the biggest provider types:

  • Laboratory: Part A Laboratory services have an overall error rate of 14.05% for the five-year period. Most errors (82.9%) for laboratory services were found to be due to insufficient documentation. Some laboratory tests with a large volume of claims tested and error rates include lipid panels (CPT 80061), hemoglobin glycosylated a1c (CPT 83036), and assays of magnesium (CPT 83735).
  • Skilled Nursing Facilities: HIPPS and HCPCS codes covering rehabilitation and therapy services continue to be the most tested codes. The overall error rate for SNF services is 11.7% and the most common reason for an error is insufficient documentation.
  • Home Health Agencies and Hospices: Hospice services provided in the patient’s home continue to be the most tested claims for both HHAs and Hospices. One key difference between the two provider types is the most common error type. For HHAs, lack of medical necessity is the most cited error reason, while insufficient documentation is the main reason for Hospices.

Part B – Durable Medical Equipment

Durable Medical Equipment (DME) providers have the highest overall error rate of the four different provider types in the CERT data at 27.4%–however, that error rate has been decreasing. Insufficient documentation has been cited as the reason for over two-thirds of the errors identified. One particular hot spot within DME is knee orthoses. These items are some of the most frequently tested and have error rates of more than 40%. 

Pharmacies can fall under the DME umbrella as well when they provide lancets, infusion pumps, and other devices used for parental nutrition for use in the patient’s home. Lancets and blood glucose reagent strips are two such items that have been frequently tested and have overall error rates of more than 40%.

Part B – Professional Services

The most common error type found in professional services testing in 2023 continues to be Insufficient Documentation. The highest level of initial and subsequent hospital evaluation and management services were two of the three most reviewed HCPCS codes—and CERT testing reveals high error rates for both. Most of these errors indicate that documentation did not support the level of E/M service billed.

Clinical laboratory services continue to be the most tested professional provider type. Various urine drug testing codes continue to have high error rates. Radiation Oncology services have seen an increase in both the number of claims tested and the error rate over the past five years.