The Reforming and Enhancing Sustainable Updates to Laboratory Testing Services Act of 2025, or RESULTS Act, seeks to ensure long-term stability for Medicare beneficiary access to clinical diagnostic laboratory tests. It achieves this by significantly improving the accuracy and feasibility of data collection used to establish private payor-based fee schedule payment rates under the Medicare program. A central provision mandates that, starting in 2028, the Secretary of Health and Human Services will collect data for "widely available non-ADLT clinical diagnostic laboratory tests" from a qualifying comprehensive claims database maintained by an independent national nonprofit entity. This independent entity must be a national nonprofit, unaffiliated with other healthcare sector organizations, and maintain a robust database containing at least 50 billion claims from over 50 private payors, representing all 50 states and D.C. The data within this database must be validated through quality assurance processes and comply with all federal and state privacy and security requirements. The Secretary is required to contract with such an entity to access this applicable information, which includes final payment rates and volumes, specifically excluding denied or erroneous payments. The bill modifies how payment rates are calculated, incorporating this new independent claims data into the weighted median of private payor rates for widely available non-ADLTs. If the Secretary cannot secure a contract with a qualifying entity or if data is unavailable, the payment rate for these tests will default to the previous year's rate, adjusted by the Consumer Price Index. For non-widely available non-ADLTs without reported data, payment will be determined through cross-walking to comparable tests or a gapfilling process. The legislation also updates data collection and reporting periods, shifting the next reporting period for laboratories to January 1, 2028, and extending the cycle to every four years. It revises the annual payment reduction limits, setting them at 15 percent for 2025 through 2028, and then reducing them to 5 percent for 2029 and subsequent years. Furthermore, the bill requires the Secretary to publicly explain payment rates, including supporting data, to enhance transparency for laboratories.