Medical Necessity, LCDs, and NCDs: What They Mean for a Claim

Medical necessity is a coverage concept: a service can be correctly coded and still not meet a payer’s coverage criteria for the patient and circumstance. For Original Medicare, National Coverage Determinations (NCDs) apply nationally, while Local Coverage Determinations (LCDs) are developed by Medicare Administrative Contractors for their jurisdictions when local policy is needed. The Medicare Coverage Database is the working tool for finding both, along with related Articles that may contain coding details. A biller’s role is to locate the applicable policy and route documentation/coding questions correctly—not to choose a diagnosis that makes the policy pass.

NCD first, LCD next, article for coding detail

An NCD establishes national Medicare coverage policy for a topic. An LCD can further address whether a service is reasonable and necessary within a MAC jurisdiction when permitted, but it cannot contradict an NCD. CMS notes that code-level claims-processing detail often appears in Billing & Coding Articles rather than the LCD itself. Search by service, CPT/HCPCS code, diagnosis, or document ID, then confirm the state/jurisdiction and effective dates. A policy from the wrong MAC can look authoritative and still be irrelevant to the claim.

Diagnosis support comes from the record, not the policy list

A Billing & Coding Article may list diagnosis codes associated with coverage, but that is not a menu from which billing can select a payable diagnosis. The patient’s record must support the diagnosis and coding rules must be followed. If the documented diagnosis is not covered for the service, the team should determine whether additional supported information exists, whether the policy was applied correctly, or whether the service is noncovered. Changing the diagnosis to fit the policy without documentation is not a denial fix.

ABN is about expected Original Medicare noncoverage

CMS’s current ABN page explains that Form CMS-R-131 is issued to Original Medicare fee-for-service beneficiaries in certain situations where Medicare payment is expected to be denied, to transfer potential financial liability when requirements are met. The form has timing and content rules; it is not something to create after a denial arrives. Organizations need a pre-service process that identifies when an ABN may be required and ensures the correct notice is delivered before the service under the applicable rules.

Medical necessity denials need a policy-to-record comparison

Start with the remittance reason and identify the exact coverage policy. Highlight the criteria the payer says were not met, then map each criterion to the record. If the documentation clearly supports the criterion and the payer appears to have overlooked it, an appeal may be appropriate. If documentation is incomplete, use the organization’s compliant documentation/query process. If the service falls outside coverage, follow the applicable financial notice and patient-responsibility rules. Do not treat every medical-necessity denial as a coding issue.

Keep policy evidence date-stamped

Coverage documents are revised. Save the policy/document ID, version or revision/effective date, MAC or payer, and the date you checked it. Avoid relying on a printed cheat sheet with no provenance. This is especially important in training: a rule that was correct in last year’s example may not control a service today. The career skill is not memorizing every NCD/LCD; it is retrieving the correct policy and explaining how it connects to the claim.

Know the boundary between ABN and good-faith estimates

An ABN is an Original Medicare beneficiary notice used in specific expected-noncoverage situations. A good faith estimate under the No Surprises Act is a different consumer-protection workflow for uninsured or self-pay individuals. They should not be merged into one generic “financial waiver.” Different rules, populations, timing, and forms apply. Billing staff should know which workflow the patient actually falls under and use the organization’s current approved notices.

Coverage research has three separate questions

When a Medicare medical-necessity issue appears, first ask whether a national coverage determination applies. If not, determine whether the patient’s Medicare Administrative Contractor has a relevant LCD, and read linked billing/coding articles when they provide coding detail. Then compare the policy to the actual record and service. A diagnosis appearing on a coverage article does not authorize staff to add that diagnosis to the claim; the medical record must support it. Coverage research tells you what evidence the policy requires, not what diagnosis you wish the patient had.

If a service is expected to be denied by Original Medicare for reasons that fit the ABN rules, the notice must be handled before the service under the applicable CMS requirements; it is not a post-denial repair tool. Keep the version of the policy and the MAC context used for the decision because LCDs and articles can change. When an appeal is necessary, show the reviewer exactly how the documented facts satisfy the cited policy rather than attaching a policy printout with no explanation.