Medicare's annual open enrollment period opens this Thursday, October 15, and closes December 7, 2026. Between those dates, people with Medicare can move between Original Medicare and Medicare Advantage, switch Medicare Advantage plans, and change Part D drug plans. Every change made in that window takes effect January 1, 2027.
For a practice, this is not a patient-facing event that happens somewhere else. It is the reason January eligibility checks return a payer nobody expected, why authorizations that were valid on December 31 are meaningless on January 2, and why the front desk spends the first three weeks of the year explaining deductibles to people who thought they had already met them. The practices that have a calm January started preparing in October.
Key takeaways
- Open enrollment runs October 15 to December 7; changes take effect January 1, 2027. A second window, January 1 to March 31, lets Medicare Advantage members switch once more.
- Confirm now which Medicare Advantage plans the practice participates with for 2027, and tell patients who ask. Patients pick plans in November believing their doctor is in network.
- Re-verify every Medicare-age patient in the first six weeks of the year, two business days ahead, and read the 271 for a plan name rather than checking for "active".
- Authorizations do not follow the patient to a new plan. Run the expiring-authorization report in early December.
- Part B and plan deductibles reset January 1. The practice that explains this in December collects it; the one that mails a statement in February does not.
What actually changes for a patient who switches
A patient who moves from Original Medicare to a Medicare Advantage plan now has a network, a plan-specific referral or authorization list, and different cost sharing. A patient who moves from one Advantage plan to another has a new member ID, a new payer ID for claims, and, in most cases, no carry-over of authorizations. A patient who leaves Medicare Advantage for Original Medicare will have Medicare as primary again, plus whatever Medigap or retiree coverage they arranged as secondary. Each of these produces a different failure at the front desk if the practice is still working from the card scanned in 2025.
There is also a second window to remember. From January 1 to March 31, the Medicare Advantage Open Enrollment Period lets people already in an Advantage plan switch once more or return to Original Medicare, with the change effective the first of the following month. So the plan you verify in January may change again in March.
Check your own participation before patients ask
Plans were required to send their members an Annual Notice of Change by September 30, and patients are reading those letters now. Over the next eight weeks, some of them will call the office and ask, "Are you in the such-and-such plan for next year?" The front desk needs a correct answer, and in many practices it does not have one, because the list of Medicare Advantage contracts lives in a drawer and nobody has checked whether any of them terminate on December 31.
Pull every Medicare Advantage contract this week and record the plan names it covers, the term, the termination notice provisions and whether either side has given notice for 2027. Call the plan's provider relations line if the contract is ambiguous, and check the plan's online directory to see how the practice is listed. Then give the front desk a one-page list of the plans the practice will and will not participate with in 2027. A patient who picks a plan in November because the directory said the practice was in network, and learns in January that it isn't, is a lost patient and a bad review, and the practice had eight weeks to prevent it.
The 2026 cost sharing that resets on January 1
For 2026, the Medicare Part B annual deductible is $283 and the standard Part B premium is $202.90 per month. CMS announces the following year's Part B premium and deductible in the fall; when the 2027 figures are published, update your estimate scripts and your patient handouts the same week. Whatever the number, every Original Medicare patient starts January owing the full Part B deductible again, and Medicare Advantage plans reset their own deductibles and out-of-pocket maximums. The first visit of the year for an Original Medicare patient without secondary coverage will usually generate a patient balance, and the practice that explains this in December collects it; the practice that mails a statement in February does not.
A worked example: a 71-year-old Original Medicare patient with no supplemental coverage has a 99214 visit on January 6. If the Medicare allowed amount for the visit in your locality is around $130, the entire amount applies to the deductible and the patient owes it. A second visit later in January would finish the deductible and start 20 percent coinsurance. Patients who met the deductible in February last year do not remember doing so, and a front desk that can say "your Medicare deductible restarted on January 1, and today's visit will apply to it" prevents the call in March.
What to change in the workflow
- Re-verify everyone in January. Run eligibility on every Medicare-age patient scheduled in the first six weeks of the year, two business days before the visit, and read the response rather than checking that it says "active". Look for a Medicare Advantage plan name in the 271 where you expected Original Medicare, or a different plan than the one on file. Update the payer, the member ID and the plan type before the patient arrives.
- Ask at check-in, every time. "Did your insurance change for the new year?" is not enough; many patients do not think of switching Advantage plans as changing insurance. Ask to see the card and compare it.
- Re-run the authorization report. Every authorization with dates running into January for a patient whose plan changed needs a new request from the new plan. Start in early December for patients who have told you they are switching.
- Check referral requirements. Some Advantage plans require a primary care referral for specialist visits; Original Medicare does not. A specialist practice should know, for every January patient, whether a referral is now required.
- Update the deductible script. Train the front desk to estimate and request the Part B deductible at the first visit of the year for Original Medicare patients without secondary coverage, and to explain what the secondary will and will not pick up for those who have one.
- Load the new payer IDs. Any Advantage plan new to your area for 2027 needs a payer record in the practice management system, with the clearinghouse payer ID, the claims address and the ERA enrollment started, before the first patient with that card arrives.
Front-desk scripts that work
We keep these short and literal, because the front desk says them fifty times a day.
- At scheduling in December: "Just so you know, a lot of people change their Medicare plan for January. If yours changes, bring the new card to your visit so we can bill the right plan."
- At check-in in January: "May I see your insurance card? Medicare plans change on January 1 and we want to be sure we have the current one."
- When a deductible applies: "Medicare's yearly deductible starts over in January. Today's visit will likely apply to it, so there may be a balance of up to the deductible amount. We can take that today or send you a statement after Medicare processes the claim."
- When a referral is now required: "Your new plan asks for a referral from your primary care office for this visit. We will contact them today; if we cannot get it before your appointment we may need to reschedule so you are not billed for the whole visit."
- When a patient asks which plan to choose: "We can tell you which plans we participate with next year. For help choosing, the State Health Insurance Assistance Program offers free counseling, and the plan itself can answer questions about its benefits."
Billing traps for the first quarter
| What you see | What usually happened | Fix |
|---|---|---|
| Medicare denies with CO-109 (not covered by this payer) in January | Patient joined a Medicare Advantage plan; Medicare is no longer primary | Re-verify, bill the Advantage plan, watch its filing limit |
| Advantage plan denies CO-197 on a service authorized in December | Authorization was with the prior plan | Request a new authorization; ask about transition-of-care provisions |
| Claims rejected for invalid member ID | New plan, new ID, old card on file | Update demographics from the eligibility response, not from memory |
| Advantage plan pays as out of network or denies for non-participation | Patient chose a plan the practice does not contract with | Confirm participation status; explain the patient's options; watch the March 31 switch window |
| Patient balances grow in February | Deductibles reset and were not requested at the visit | Estimate and collect at time of service; statement within 7 days of the remittance |
Questions we hear
Should we call every Medicare patient in December?
Call the ones with authorizations or ongoing treatment plans that run into January, and the ones scheduled in the first two weeks of the year. For everyone else, the scheduling script and a January eligibility run are enough.
Can the front desk tell patients which plan to pick?
No, and they should say so. The office can confirm which plans the practice participates with and refer questions about plan choice to the State Health Insurance Assistance Program or the patient's own plan. Anything more is advice the practice is not licensed to give.
Who owns this?
The front-desk lead owns verification and the scripts; the billing lead owns the authorization re-run and the January denial watch; the practice manager owns the participation list. If eligibility work is already stretched, this is the season when practices most often bring in outside billing support, and the pre-visit eligibility check is the first thing we would want to see in place before January 4.
What to do this month
- Pull every Medicare Advantage contract, confirm 2027 participation, and give the front desk a one-page list of plans the practice is and is not in.
- Add the December scheduling script to the front-desk routine now, so patients hear it at every call between now and the end of the year.
- List every patient with an authorization or treatment plan running past December 31 and set a reminder to re-request in the first week of December.
- Check that the practice management system can run eligibility two business days ahead in batch, and schedule it for the first six weeks of January.
- Draft the deductible handout with the 2026 figures and a blank for the 2027 numbers, ready to update the week CMS publishes them.
