A five-physician internal medicine group runs a small in-office laboratory: chemistry panels, A1c, urinalysis, a hematology analyzer. PAMA lab data reporting 2026 applies to it, and nobody there knows. The practice manager received an email in April about "CLFS private payor rate reporting" and filed it under things that apply to hospitals and reference labs. It does not. The practice bills Medicare Part B for lab tests under its own NPI, collected well over $12,500 in Medicare lab payments in the first half of 2025, and derives all of its Medicare revenue from the physician and clinical lab fee schedules. That makes it an applicable laboratory, and the PAMA lab data reporting 2026 window that opened on May 1 closes this Friday, July 31, 2026.
We are writing this on Monday, four days out, because we have had this conversation with several practices in the last two weeks and the answer has been the same each time: they had no idea it applied to them. If you have an in-office lab, read the two tests below today. If you meet them, you have four days to register, upload and certify. If you do not meet them, you can document why and move on.
This is operational guidance from people who work with practice billing data; it is not legal advice, and the CMS frequently asked questions document, updated July 14, 2026, is the authority on the details.
Key takeaways
- The 2026 data reporting period runs May 1 through July 31, 2026, and covers private payor rates and volumes for laboratory tests paid during the data collection period of January 1 through June 30, 2025.
- An applicable laboratory bills Medicare Part B under its own NPI, receives more than 50 percent of its total Medicare revenue from the clinical laboratory fee schedule and the physician fee schedule combined, and received at least $12,500 in Medicare clinical laboratory fee schedule revenue during the six-month collection period; for physician office labs billing under a group tax ID, the $12,500 test is applied at the TIN level.
- Reporting is done through the CLFS Data Collection System with one submitter and one certifier per TIN and NPI, and the statute provides for civil monetary penalties of up to $10,000 per day, adjusted for inflation, for failure to report or for misrepresentation.
- Section 6226 of the Consolidated Appropriations Act, 2026 changed the schedule: no clinical lab fee schedule payment reductions in 2026, and reductions in 2027 through 2029 capped at 15 percent per year per test.
What PAMA lab data reporting 2026 is
A glossary line for the clinicians. PAMA is the Protecting Access to Medicare Act of 2014. Section 216 changed how Medicare pays for clinical diagnostic laboratory tests: instead of historical fee schedules, Medicare sets each test's payment at the weighted median of what private payers pay, based on data that laboratories themselves report. The clinical laboratory fee schedule, or CLFS, is the Medicare payment list for those tests. Every few years, laboratories that meet the definition of an applicable laboratory must report, for each test, every private payor rate they were paid and the volume at each rate. CMS uses that data to reset the CLFS for the following three years, with statutory caps on how much a rate can fall in any one year.
The reporting cycle was delayed repeatedly after 2017 by legislation, which is why many practices that reported once, or never did, have not thought about it for years. This year it is back. The data being reported now, from the first half of 2025, will set CLFS rates for 2027, 2028 and 2029.
The two tests: are you an applicable laboratory
| Test | Rule | What it means for a physician office lab |
|---|---|---|
| Bills Medicare under its own NPI | The laboratory bills Medicare Part B under its own National Provider Identifier (hospital outreach labs use type of bill 14X) | A physician group whose in-office tests are billed on the group's claims under the group NPI meets this; the group NPI is the reporting entity, and the analysis is at the TIN level |
| Majority of Medicare revenues | Medicare CLFS revenues plus Medicare physician fee schedule revenues are more than 50 percent of total Medicare revenues for the entity during the collection period | Almost every physician practice meets this, because nearly all of its Medicare revenue comes from the physician fee schedule; the test was designed to exclude hospitals, whose revenue is mostly inpatient and outpatient prospective payment |
| Low expenditure threshold | At least $12,500 in Medicare CLFS revenue received during the six-month data collection period (January 1 to June 30, 2025) | About $2,100 a month in Medicare lab payments; a practice with a chemistry analyzer and a Medicare-heavy panel often exceeds this; a practice doing only urine dips and rapid strep usually does not |
To check the third test, run a payments report for January 1 through June 30, 2025, filtered to Medicare Part B as payer and to laboratory CPT codes (the 80000 series plus the G codes and other codes on the CLFS), and total the payments received in that window. Note that it is payments received, not charges billed, and it is traditional Medicare, not Medicare Advantage. If the total is $12,500 or more and you meet the other two tests, you are an applicable laboratory. If it is below, document the report and the calculation, sign and date it, and keep it; CMS may ask how you concluded you were exempt.
What has to be reported
For each HCPCS code on the CLFS that the laboratory was paid for by private payors during the collection period, the "applicable information" is: the HCPCS code, each distinct private payor rate at which final payment was made, and the volume of tests paid at each rate. Private payor means commercial insurers, Medicare Advantage plans and Medicaid managed care plans; traditional Medicare and Medicaid fee-for-service payments are excluded. A rate is reported once payment is final, meaning after any appeals; a claim denied in full is not a rate. Patient cost sharing is included in the rate, since the rate is what the payer allowed, not what it paid the practice.
In practice this means pulling remittance data for the six-month window, filtering to lab codes and private payors, grouping by code and by allowed amount, and counting. A practice with three lab codes and four payers may have a few dozen rows. Larger in-office labs have hundreds. The CMS data reporting template defines the format. Do not report Medicare Advantage rates under the Medicare exclusion; they count as private payor rates, which surprises people.
How to report
Reporting goes through the CLFS Data Collection System, reached through the CMS Identity Management (IDM) system. Each TIN and NPI combination needs exactly one submitter, who uploads the data, and one certifier, who attests to its accuracy; the same person cannot hold both roles for the same entity. Both need IDM accounts, and the entity has to be registered in the CLFS module with its TIN and NPI before anything can be uploaded. CMS posted submitter and certifier user guides, the applicable HCPCS code list and the template. If you have four days and no IDM accounts, start with the accounts this morning; identity verification is the slow step.
The certifier is a real role with real exposure. The statute provides for civil monetary penalties of up to $10,000 per day, an amount adjusted annually for inflation, for failure to report or for misrepresentation or omission in reporting. CMS has said it will exercise discretion, but the certifier should be an owner or officer who has actually looked at the data, not a biller who was handed a login.
What the 2026 appropriations law changed
Congress passed Section 6226 of the Consolidated Appropriations Act, 2026 on February 3, 2026. It left this year's reporting requirement in place but changed the payment consequences. There is no phase-in reduction to CLFS rates in 2026. Beginning January 1, 2027 and running through 2029, a test's payment may not be reduced by more than 15 percent per year compared with the prior year's rate. For a practice with an in-office lab, that means the data reported this month will set 2027 rates, and any test whose private payor median has fallen since the last cycle will step down by no more than 15 percent a year over the three-year period. CMS has said it will publish preliminary 2027 CLFS rates for comment later this year.
Our opinion: the cap softens the blow, but a 15 percent cut three years running is still 39 percent, and practices whose in-office labs are marginal at current rates should be modeling that now rather than in December. The reported data also becomes a benchmark: your commercial payers can see, in aggregate, what the market pays for each test.
Questions we hear
Our lab tests are billed by a reference laboratory, not by us. Do we report?
No. If the reference lab bills Medicare for the tests, the reference lab is the applicable laboratory for those tests. You report only tests your practice bills under its own NPI. Practices that do some tests in house and send others out report only the in-house tests.
We reported in a prior cycle. Do we have to again?
Yes, if you meet the tests for this collection period. Each cycle stands alone. A practice that fell below $12,500 in Medicare lab revenue in the first half of 2025 is exempt this cycle even if it reported before; a practice that grew into the threshold must report now.
What if we miss Friday?
Report as soon as you can and document why you were late. CMS has authority to impose penalties and has historically focused on entities that failed to report at all rather than those that reported late in good faith, but that is a description of past discretion, not a promise. Our RCM audit team can pull the payments analysis quickly for practices that need the threshold answer today, and our medical billing clients with in-office labs have had this on the calendar since May.
What to do this week
- Today: run Medicare Part B payments for lab codes for January 1 to June 30, 2025 and compare the total to $12,500; document the result either way.
- If you meet the tests, create IDM accounts for a submitter and a certifier this morning and register the TIN and NPI in the CLFS module.
- Pull private payor remittances (commercial, Medicare Advantage, Medicaid managed care) for lab codes in the same window and build the code, rate and volume table in the CMS template.
- Have the certifier review the table against a sample of remits before certifying, and submit before the close on Friday, July 31.
- Whether or not you report, model your top five in-office tests under a 15 percent annual reduction for 2027 through 2029 and decide whether each still makes sense to run in house.
