Medicare has been paying laboratories roughly 16 percent more than private insurers pay for the same clinical tests, according to the agency’s own comparison of its payment data against private-sector rates. The Centers for Medicare & Medicaid Services released that finding on September 21, 2026, alongside preliminary 2027 lab payment rates designed to close most of the gap, which the agency estimates will save taxpayers about $1 billion a year once fully phased in. The gap does not typically show up as a bill to an individual Medicare patient, since Medicare usually covers clinical lab tests without coinsurance, but it is a direct hit to the trust fund that keeps Part B premiums and Medicare’s finances stable for everyone enrolled.
What CMS Disclosed on September 21
The finding comes straight from CMS, not from an outside inspector general or watchdog office. The CMS press release states plainly that the agency is “releasing the data and information used to determine the preliminary 2027 Medicare payment rates for laboratory services showing that Medicare has been paying about 16% more for laboratory services than private payors.” CMS Administrator Dr. Mehmet Oz put it more bluntly: “Taxpayers and Medicare patients have been paying excessive rates to labs for years, but with some help from Congress, CMS is working to ensure that Medicare isn’t paying more than private insurers for the exact same tests.” Oz added that publishing the underlying data is meant to provide “greater transparency into the actual market rates for laboratory services, rooting out waste, and supporting better-informed pricing decisions across the healthcare system, including Medicaid and Affordable Care Act Exchanges.”
Where the help is written down: The programs that lower Medicare costs each run on a different form and a different office, and no single notice lists them together. See the state cost-help packs in The Medicare Cost & Coverage Protection Kit.
The Law Behind the 16 Percent Gap
Congress required CMS in 2014, under the Protecting Access to Medicare Act, to set most rates on the Clinical Laboratory Fee Schedule using what private payors actually pay for the same tests, with rates normally due to update every three years. According to CMS, “due to legislative delays, that process has been used only once for these tests” between 2014 and this year, which let Medicare’s rates and the private market drift apart as private-sector prices for many lab tests fell over the following decade. Section 6226 of the Consolidated Appropriations Act, 2026 restarted the cycle, setting a new data collection period of January 1 through June 30, 2025 and a reporting period of May 1 through July 31, 2026 — the data behind this month’s 16 percent comparison.
The Data Behind the Number
CMS’s companion fact sheet shows how the 16 percent figure was built. In the 2026 reporting cycle, 6,411 laboratories submitted private-payor rate data covering 1,947 billing codes, and CMS was able to calculate a weighted median private-payor rate for 1,528 of those codes, or 78.5 percent. Averaged across every code reviewed, the potential change to current Medicare rates comes out to about 16 percent lower — CMS’s fact sheet lists it as “~16% lower” in its own key-statistics table, matching the press release’s rounder framing. The gap is not uniform: chemistry tests would fall about 16 percent, molecular pathology about 22 percent, genomic sequencing about 23 percent, microbiology and immunology both about 19.3 percent, while proprietary laboratory analyses would fall only about 2.4 percent. Of the codes with usable data, 1,171 would see Medicare’s rate drop, 186 would see it rise, and 169 would stay the same.
Why the Fix Phases In Over Years, Not All at Once
Federal law caps how fast Medicare can cut a single lab test’s payment rate: no more than 15 percent in any one year, through 2029, a limit written into the Consolidated Appropriations Act, 2026’s amendments to the underlying statute. Because Medicare has been overpaying by about 16 percent on average, and tests like molecular pathology and genomic sequencing are running further out of line than that average, CMS says it will phase in the reductions across calendar years 2027 through 2029 rather than cutting rates to the full private-sector level in a single year.
What’s Preliminary Versus What’s Locked In
The 16 percent overpayment finding itself is not up for debate — CMS has published it as a completed comparison. What remains preliminary is the specific 2027 payment rate for each individual lab test. The public has 30 days from September 21, 2026, to review and comment on the preliminary rates and the underlying data. For lab tests that had no private-payor data reported to CMS at all, the agency held a separate public meeting on September 15 and 16, 2026, to work out how those tests should be priced, with determinations due in early October followed by their own 30-day comment window. CMS says it expects to finalize the full set of CY2027 clinical laboratory rates in November 2026, taking effect January 1, 2027.
The Household Money Angle: A Trust Fund Problem More Than a Copay Problem
Because Medicare Part B generally pays clinical diagnostic laboratory tests without a beneficiary copay or deductible, most Medicare patients will not see a line-item change on a bill from this correction. The money consequence runs through the Medicare trust fund instead: CMS’s estimated $1 billion in annual savings, once the phase-in is complete, is money that would otherwise have gone to labs at above-market rates and that CMS says helps protect the program’s overall finances, which in turn factor into future Part B premium calculations. Beneficiaries in Medicare Advantage or with private coverage may see a more indirect effect, since Oz specifically named Medicaid and Affordable Care Act Exchange pricing as areas the same private-payor data could inform going forward.
Finding the Programs That Actually Lower a Medicare Bill
A national correction to what Medicare pays labs does not change what an individual pays a pharmacy or a doctor’s office, and it says nothing about the separate assistance programs that reduce a specific person’s Medicare costs. Those programs are scattered across Medicaid offices, Social Security and state agencies, each with its own form and its own income rules.
The Medicare Cost & Coverage Protection Kit is a 10-page kit built around 51 state Medicare cost-help packs and the new Part D out-of-pocket cap, plus the prior-authorization appeal steps.
See the state-by-state cost-help programs in The Medicare Cost & Coverage Protection Kit.
This article was produced with AI assistance and reviewed by a human editor. Figures are linked to their primary sources.
