Goodbye G2211, hello B1 and B2: what the 2027 Medicare Physician Fee Schedule means for primary care

Starting Jan. 1, 2027, Medicare will no longer pay G2211 as a separate add-on code. Under the calendar year 2027 Medicare Physician Fee Schedule (MPFS) final rule released Nov. 4, the Centers for Medicare & Medicaid Services (CMS) will instead pay for visit complexity through two modifiers added to the evaluation and management (E/M) code itself. Modifier B1 raises the visit payment by 16%. Modifier B2 raises it by 32%, but only practices in Medicare Shared Savings Program (MSSP) accountable care organizations (ACOs) or the new Long-term Enhanced ACO Design (LEAD) model can use it.

For primary care, this matters more than a typical coding change, according to CMS’ 2027 MPFS fact sheet published with the final rule. It changes how the longitudinal-care payment rises with visit level. It also creates a two-tier fee schedule for the same visit, depending on whether the practice belongs to an ACO. And it has effects on shared savings that ACO leaders should model before anyone tells clinicians to "always add B2."

How the new modifiers work

The clinical criteria stay the same. The modifier is reported in the same situations as G2211: The clinician is the continuing focal point for the patient's care, or is providing ongoing care for a single serious or complex condition. The proposed policy carried forward G2211’s restrictions when the underlying E/M visit is billed with modifier 25. Under those restrictions, the new longitudinal-care modifier cannot be billed with an E/M service carrying modifier 25, except when the accompanying service is an Annual Wellness Visit, vaccine administration, or another eligible Medicare Part B preventive service. CMS’ final-rule fact sheet confirms adoption of the replacement modifiers but does not separately detail these billing edits.

The change is in the math. G2211 paid a flat amount no matter the visit level. The modifiers pay a percentage of the base E/M code, so a level 4 or 5 visit earns more than a level 2. On a $100 visit, B1 adds $16 and B2 adds $32. CMS describes this as an equal percentage increase across all E/M levels and expects little overall payment impact from B1, because existing G2211 volume simply moves to the modifier. For a typical primary care visit mix, B1 is roughly neutral compared with today's flat add-on. B2 is not. It is a real increase in payment for every eligible visit.

Who qualifies for B2?

B2 is limited to practitioners participating in an MSSP ACO and participant providers in a LEAD model ACO. CMS says the extra payment recognizes the added costs ACO clinicians carry, including accountability for total cost of care and quality reporting tied to longitudinal care.

Three details matter:

• B2 applies to every Medicare patient, not just ACO-assigned ones. An MSSP clinician can bill B2 for any eligible visit with a fee-for-service Medicare beneficiary, whether or not that patient is assigned to the ACO.
• Using B2 is voluntary. Practices can still bill B1.
• "Advanced APM" status alone does not qualify you. Eligibility is defined by MSSP or LEAD participation, not by Advanced Alternative Payment Model (APM) or Qualifying APM Participant status in general. Practices outside those two programs get B1 only.

Specialists in MSSP ACOs who manage a serious or complex condition over time can also bill B2. In multispecialty ACOs, this will not be a primary care-only benefit.

The catch: B2 counts against the ACO

This is the part most practice-level summaries will miss. CMS states that claims billed with B2 count toward beneficiary assignment, historical benchmark expenditures, and performance-year expenditures in both MSSP and LEAD.

In plain terms, every B2 dollar paid for an assigned beneficiary raises that ACO's performance-year spending. For ACOs whose current benchmarks were set from years before B2 existed, part of the extra payment may come back out of shared savings. Benchmark trend adjustments may offset some of it. How much depends on regional and national B2 uptake, and no one can know that yet.

That does not make B2 a bad deal. The payment arrives with every visit and is certain. Shared savings arrive 18 months later and are not. For a cash-constrained independent practice, getting the money now is worth something. But ACO boards should:

• Model B2's likely effect on performance-year spending per assigned beneficiary.
• Decide how B2 revenue fits into their shared savings distribution formula. A practice that bills B2 heavily may be drawing down a pool that other practices share.
• Track whether higher primary care allowed charges shift plurality assignment toward ACO clinicians. Assignment uses allowed charges for primary care services, and B2 claims are explicitly included.

The bigger picture for 2027

The B2 premium comes in a year of cuts. The 2027 conversion factor falls 2.31%, to $32.63, for clinicians who are not Qualifying APM Participants. It falls 1.83%, to $32.95, for those who are. Most of the drop reflects the expiration of Congress's one-year 2.5% increase for 2026.

For a primary care practice outside an ACO, B1 roughly preserves the G2211 value while the base rate shrinks. For an MSSP practice that bills B2 consistently, the extra 16 percentage points on eligible visits more than offsets the conversion factor cut. That is a clear financial signal from CMS: Join an ACO.

Patients will notice too. The 20% Part B coinsurance applies to the higher visit payment, so B2 visits cost beneficiaries more. Starting April 1, 2027, CMS-approved ACOs may reduce or eliminate Part B cost sharing for assigned beneficiaries, which could soften that effect .

What practices should do now

• Update charge masters and EHR billing rules to replace G2211 with B1 or B2 before Jan. 1.
• Confirm your MSSP or LEAD participant status at the taxpayer identification number and national provider identifier level. Billing B2 when you are not eligible is a compliance problem, not a coding slip.
• Check payer policies. Medicare Advantage plans and commercial payers that copied G2211 may not recognize B1 or B2 right away.
• Ask your ACO how it will handle B2 in benchmark modeling and savings distribution.

CMS has also sought comments on rethinking the relative value of primary care and introducing prospective primary care payments within MSSP. B2 may represent an initial step toward a payment system that finally recognizes primary care as essential infrastructure — not simply another billable service, but the foundation of coordinated, effective, and accountable care. Higher payments for qualifying ACO clinicians are a welcome investment in that foundation. Still, because those payments also count toward ACO spending, the financial benefit will depend on their effect on shared savings. Primary care should welcome the recognition and the investment — while checking the math.

Robert Resnik, M.D., MBA, is a board-certified internal medicine physician practicing in Cary, North Carolina. He earned his medical degree from Eastern Virginia Medical School and completed his residency at East Carolina University. He also holds an MBA from Duke University.