Laboratory billing looks straightforward — you run a test, you bill a code. But the reality involves PAMA rate adjustments, LCD restrictions, panel bundling rules, and payer policies that vary wildly. Getting it wrong at scale adds up fast.
If you're working through these issues, our specialty billing services can help you address them systematically.
The Protecting Access to Medicare Act set up a system where clinical lab fee schedule rates are benchmarked against private payer rates. The rate reductions phased in over multiple years, and labs that weren't tracking their PAMA exposure have taken a quiet revenue hit they might not have fully analyzed.
For 2026, make sure your billing team knows the current CLFS rates for your top-billed codes. If your lab performs high volumes of metabolic panels, lipid panels, or CBC with differentials, even small rate differences across thousands of claims are material.
CMS has explicit rules about when you must use a panel code versus billing individual components. If you run all the components of a Basic Metabolic Panel (CPT 80047 or 80048), you're required to bill the panel code — not each individual test separately. Billing the components individually to get higher reimbursement is called unbundling, and it's a compliance violation.
The reverse also applies: don't use a panel code when you only ran some of the components. Bill only what you actually performed.
Local Coverage Determinations govern what diagnoses support coverage for specific lab tests. If you're billing a test without a covered ICD-10 code, you're looking at a denial — or worse, a post-payment recovery if auditors find a pattern.
Genetic testing has particularly tight NCD restrictions. The coverage for BRCA testing, pharmacogenomics, and other molecular tests is specific. Running a test that a physician ordered without verifying coverage first puts your lab at risk, not just the ordering physician.
When you know Medicare won't cover a test (because the diagnosis doesn't meet LCD criteria, or it's non-covered), you need an ABN before you run the test. The ABN transfers financial responsibility to the patient. Without it, if Medicare denies, you can't bill the patient — the cost is yours.
Labs that see high denial rates on specific tests should analyze whether those tests need routine ABN workflows. Some labs are now integrating ABN generation into their LIS (laboratory information system) based on the ordered test and diagnosis code combination.
Reflex testing (where a second test is automatically run based on the first result) needs to be ordered in advance or have a standing order that covers the reflex. You can't bill a reflex test that wasn't authorized. And the clinical indication has to flow through — the reflex test needs its own billing support even if it's triggered automatically.
Physician offices with in-office labs face the same panel bundling and LCD rules as independent labs. CLIA certificate level affects which tests you can perform and bill. A CLIA waiver covers waived complexity tests only — don't bill moderate-complexity test codes on a waived certificate.
Some labs bill before results are finalized. CMS requires that the service was actually performed — meaning the specimen was collected and processed. Billing in advance of specimen collection is a compliance issue. Build billing workflows around result confirmation, not order entry.
| Common Lab Denial Reason | Root Cause | Fix |
|---|---|---|
| Diagnosis not covered | LCD mismatch | LCD review at order entry |
| Unbundling | Panel components billed separately | Panel logic in billing system |
| No ABN on file | Non-covered test, no waiver | ABN workflow by test/diagnosis |
| Duplicate claim | Reflex test billed twice | Reflex billing audit |
The billing gaps most practices don't catch until they show up as denials. Get the checklist — free, no spam.
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