December 2025 OIG Work Plan Updates: What Compliance Teams Should Watch

December 2025 saw just a few new additions to the HHS OIG Work Plan. Let’s look at some of the highlights. 

Medicaid Eligibility

According to the non-profit organization Kaiser Family Foundation, over 83 million individuals in the United States use Medicaid as their primary health care coverage. Medicaid is funded by taxpayers both at the state level and the federal government. The program is administered at the state level. Eligibility for Medicaid is limited to U.S. citizens and certain lawfully present immigrants. Federal funds cannot be used to cover undocumented immigrants (see more here: https://www.kff.org/immigrant-health/how-states-verify-citizenship-and-immigration-status-in-medicaid/).  

Medicaid eligibility depends on a number of criteria including requirements related to income, residency, citizenship, immigration status, and documentation of citizenship. As each state administers its own Medicaid program, they must verify individuals' eligibility information, such as citizenship and immigration status, with the Social Security Administration and the Department of Homeland Security. Any discrepancy between an individual's attested citizenship or immigration status and the information verified by the state must generally be resolved within a 90-day timeframe known as the reasonable opportunity period.  

With the announcement of this Work Plan item, OIG intends to determine whether selected states determined Medicaid eligibility for enrollees based on citizenship or immigration status and claimed Federal Medicaid reimbursement in accordance with Federal and State requirements. 

Home Health Payments

Medicare payments for home health services have steadily increased over recent years. In 2024, Medicare payments to home health agencies (HHAs) exceeded $16 billion. Payments to HHAs are adjusted by the case mix of the enrollees receiving services. HHAs receive higher payments when diagnosis codes indicate specific comorbidities, and CMS data show that about 70 percent of claims received a comorbidity adjustment in 2023 and 2024.  

OIG wants to know if there is anything inappropriate about this high percentage of claims with a comorbidity adjustment are legitimate. To determine the extent of potential improper HHA coding and potential savings, OIG plans to analyze a subset of HHA claims that received increased payments for select comorbidities and assess whether non-HHA claims also identified the same condition. 

Part B Drug Payments

If you have been involved with health care compliance, coding, billing or reimbursement for any length of time, you have likely heard the phrase “average sales price,” or ASP. 

Congress established the average sales price (ASP) as the basis for Medicare Part B drug reimbursement. When they did so, they also provided a mechanism for monitoring market prices and limiting potentially excessive Medicare payment amounts. The Social Security Act requires OIG to compare ASPs with average manufacturer prices (AMPs) and widely available market prices, if any.  

If OIG finds that the ASP for a drug exceeded the AMP by five percent in the two previous quarters or three of the previous four quarters, the Secretary of Health and Human Services may substitute the reimbursement amount with a lower calculated rate. Over the past decade, OIG has produced annual reports aggregating the results of their mandated quarterly ASP-to-AMP comparisons.  For example, a recently published OIG report from November 2025 (see here: https://oig.hhs.gov/documents/evaluation/11272/OEI-03-26-00030.pdf) concluded that 12 drug codes met CMS’s price-substitution criteria by exceeding the five percent threshold for two consecutive quarters or three of the previous four quarters. 

This Work Plan item is an annual report that will quantify the savings to Medicare and its beneficiaries that result directly from CMS’s price substitution policy using 2024 ASPs. The report may also recommend ways that Medicare can achieve additional savings.

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