Medicare Participation for 2027: What L.A. Physicians Should Review Before Dec. 31

Check your status, review local payment rates, and prepare your billing team before making a change.

For Los Angeles physicians reassessing their Medicare participation, December 31 is a deadline with consequences for both practice revenue and patients’ financial responsibility. Physicians changing between participating and non-participating status for 2027 must submit the appropriate signed notice or agreement to Noridian postmarked by December 31, 2026. Changes take effect January 1, 2027. Submit early and retain proof of mailing. Deadline details.

The decision comes as Medicare’s 2027 Physician Fee Schedule lowers the conversion factor by 2.31% for clinicians who are not qualifying Advanced Alternative Payment Model participants and 1.83% for qualifying participants. These figures describe changes in the base payment calculation; the effect on an individual practice will depend on its services and other payment adjustments. CMS final rule.

For L.A. practices, start with the local numbers

Los Angeles and Orange counties share Medicare payment locality 18, covering the Los Angeles–Long Beach–Anaheim metropolitan area. Physicians reviewing reimbursement should use that locality when looking up applicable rates. CMS locality guidance.

Ask your billing team to compare 2027 allowances for your most frequently billed services with current payments, using the appropriate office or facility setting. Assess what those changes mean for revenue, collection costs, and patients’ out-of-pocket obligations before choosing a different participation status.

Understand what each option means

Participating physicians accept Medicare’s approved amount as payment in full for covered services subject to the agreement, while collecting applicable patient cost sharing. Participation requirements.

Non-participating physicians remain enrolled in Medicare. They can generally accept assignment claim by claim where permitted, but their approved amounts for many physician services are 95% of participating amounts. Eligible unassigned claims are subject to a limiting charge—generally 115% of the non-participating amount. Non-participation does not remove Medicare billing requirements. Non-participation rules.

Take the correct action

Noridian, the Medicare contractor serving California, outlines these steps:

• Keeping your current participating or non-participating status: No annual action is required.

• Changing from non-participating to participating: Submit the signed CMS-460 participation agreement, postmarked by December 31.

• Changing from participating to non-participating: Submit a signed written request to Noridian, postmarked by December 31.

Physicians who reassign Medicare benefits to an organization take on that organization’s participation status. If you bill through a group, confirm its election with your practice administrator before submitting an individual request. Group participation requirements.

Noridian also advises holding billing when changing status until notification of the change arrives. Build that processing period into your cash-flow planning. Noridian enrollment instructions.

Considering opting out? Start earlier

Opting out requires a separate affidavit and compliant private patient contracts. For physicians recorded as participating in PECOS, Noridian generally requires submission at least 30 days before the next calendar quarter begins. Physicians seeking a January 1 effective date should confirm requirements promptly; waiting until December 31 would be too late under that rule. Opt-out timing.

Help patients understand any change

If your decision changes patients’ billing responsibilities, prepare clear explanations before implementation. For Los Angeles County patients who need independent Medicare counseling, the Center for Health Care Rights provides free assistance through HICAP. Local patient assistance.

LACMA members can also explore available practice and payer support before making a decision. Member resources.