How to Find Your MAC and LCD Before Billing
To confirm Medicare coverage before billing, identify your MAC by the state of service, check whether a National Coverage Determination exists first (an NCD overrides any LCD), then open the Local Coverage Determination and its billing-and-coding article in the CMS Medicare Coverage Database to verify covered ICD-10 codes, frequency, and documentation.
- Check first
- Does an NCD exist? NCD overrides LCD
- Where to look
- CMS Medicare Coverage Database (MCD)
- Codes live in
- Billing & coding article, not the LCD
- Filter by
- Your state or MAC
How do you identify your MAC?
Coverage rules are set by jurisdiction, so the first question is always which contractor governs the claim. For Part A and Part B, it is the A/B MAC for the state where the service was furnished; for durable medical equipment, it is the DME MAC for the beneficiary's permanent residence. Look it up on the CMS "Who are the MACs" page, which lists each jurisdiction, its contractor, and its states.
Do not assume it is stable. CMS recompetes MAC contracts on multi-year cycles, and jurisdiction lines have shifted over time, so a contractor you billed last year may not be the one today. The Medicare Administrative Contractor entry has the current jurisdiction table, but the CMS page is the authoritative source to confirm before you rely on it.
How do you find and read the right coverage policy?
Work the CMS Medicare Coverage Database in order. Check for a national policy first, because an NCD outranks any LCD and an LCD cannot conflict with it. Only where no NCD exists do you drop to your MAC's LCD. The LCD vs NCD entry covers that hierarchy; here is the workflow.
- Open the Medicare Coverage Database and search the CPT/HCPCS code or keyword; filter to your state or MAC.
- Check for an NCD first. If one exists, it controls nationwide, so read it and its transmittal for frequency and criteria.
- If no NCD applies, open the LCD (ID starts with "L") for your MAC to read the clinical "reasonable and necessary" narrative.
- Open the companion billing-and-coding article (ID starts with "A") for the actual covered ICD-10 list, frequency limits, and documentation requirements.
- Confirm the code you are billing appears on the covered list, and check the LCD's effective and revision dates before you submit.
What does this look like in practice?
Take a molecular or specialty lab test. Under one A/B MAC there is a detailed LCD with a specific covered-diagnosis list, a frequency limit, and a documentation checklist; billing the test with a listed diagnosis pays cleanly, and billing it with an unlisted one denies reasonable and necessary. Cross a state line into another MAC's jurisdiction and there may be no LCD at all for that same test, which does not mean automatic payment. The MAC decides medical necessity claim by claim and can still request the record.
The practical takeaway: confirm coverage per jurisdiction, every time, before submission. Where a covered indication is documented, load the LCD/article code pairs into order entry so the right diagnosis reaches the claim. Where denial is genuinely likely, an ABN with modifier GA shifts liability to the patient instead of forcing a write-off. Checking the database first turns a guess into a decision you can defend.
Frequently asked questions
In the CMS Medicare Coverage Database at cms.gov/medicare-coverage-database. Search by CPT/HCPCS code, keyword, or document ID, then filter to your state or MAC. LCD IDs start with "L" and the companion billing-and-coding articles start with "A." Always open the article, because since 2019 that is where the payable ICD-10 code lists, frequency limits, and documentation requirements actually live.
Check for a National Coverage Determination first. If CMS has issued an NCD on the service, it controls nationwide and an LCD cannot conflict with it, so the NCD sets the floor for coverage and any frequency rules. Only when no NCD addresses the service do you rely on your MAC's LCD and its article. The Medicare Coverage Database lets you search both in one place.
No LCD does not mean automatic coverage or automatic denial. Where neither an NCD nor an LCD exists, the MAC decides medical necessity claim by claim under the general "reasonable and necessary" standard, and may still request records. Document the indication as if it will be reviewed, and consider an ABN with modifier GA when denial is a real possibility.
Sources & further reading
Reviewed by the ImmediCare Solutions RCM team
Certified billers and coders handling claims across 50+ specialties nationwide. This entry is reviewed against current payer policy and CMS rules. Last review: Jul 5, 2026.
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