Medicare pays CRNAs directly under Part B for anesthesia and related services, at the same anesthesia fee schedule rates paid to physicians. A non-medically directed CRNA case bills with the QZ modifier and pays 100 percent of the fee schedule amount.
CRNAs have had direct Medicare billing rights since 1989, when the Omnibus Budget Reconciliation Act of 1986 took effect. CRNAs were the first nursing specialty to win direct Medicare reimbursement. Here is how the money actually flows.
Key points
- QZ cases pay 100 percent of the fee schedule, same as a physician.
- Medically directed cases split payment 50/50.
- CRNAs must accept Medicare assignment; no balance billing.
- Opt-out status changes supervision rules, never the payment.
Part B basics
Anesthesia professional services are Part B services. For each covered service Medicare pays 80 percent of the allowed amount, and the patient (or a secondary plan such as a Medigap policy) owes the remaining 20 percent after the Part B deductible.
CRNAs enroll in Medicare individually, get a provider transaction access number through PECOS enrollment, and either bill under their own number or reassign billing rights to a group or employer.
Assignment
CRNAs are required to accept assignment on Medicare claims. Accepting assignment means you take the Medicare allowed amount as payment in full: 80 percent from Medicare, 20 percent from the patient or secondary coverage. You cannot balance bill a Medicare patient above the allowed amount.
How the payment amount is set
Anesthesia services are priced by a formula rather than standard RVUs:
(Base units + time units) x anesthesia conversion factor
Base units come from the CMS anesthesia base unit file for the CPT code. Time units are anesthesia minutes divided by 15, with fractional units allowed. The 2026 national anesthesia conversion factor is $20.4976 ($20.5998 for qualifying APM participants), adjusted by geographic locality. Full walkthrough with an example: anesthesia base units and time units.
Non-anesthesia services that CRNAs bill, such as certain invasive lines or chronic pain services where state scope and payer policy allow, are priced under the regular physician fee schedule using RVUs instead.
How CRNA payment compares to anesthesiologist payment
For the anesthesia service itself, there is no payment differential. The same case with the same time pays the same total whether billed AA (anesthesiologist personally performed) or QZ (CRNA, not medically directed). Medicare values the service, not the credential.
What changes is how the money splits when both provider types are on a case:
| Billing model | Total paid | Split |
|---|---|---|
| AA, physician alone | 100% of fee schedule | All to physician |
| QZ, CRNA not medically directed | 100% of fee schedule | All to CRNA |
| QY/QK + QX, medical direction | 100% of fee schedule | 50% physician, 50% CRNA |
| AD, medical supervision | Reduced | Physician limited to 3 base units, plus 1 time unit if present at induction |
Details on the models and the seven TEFRA steps: medical direction vs medical supervision.
Opt-out states: what they do and do not change
Separately from payment, Medicare's hospital and ASC conditions of participation require physician supervision of CRNAs unless the state governor opts out. As of September 2026, 27 states plus the District of Columbia and Guam have opted out, with Vermont, Ohio, and DC the most recent additions, and Utah and Wyoming partial.
Opt-out status does not change what Medicare pays. QZ claims pay 100 percent of the fee schedule in every state. Opt-out matters for facility certification and staffing models, which is why all-CRNA practices are easiest to run in opt-out states. See CRNA opt-out states.
Rural pass-through
Small rural hospitals and critical access hospitals that qualify can receive reasonable-cost reimbursement for CRNA services through the CRNA pass-through program, instead of fee schedule billing. Qualification criteria include low surgical volume and employing or contracting with no more than one full-time-equivalent CRNA; the exact criteria and election process are set by CMS and administered through the hospital's MAC. If you work with a rural facility, confirm its current status with the facility and its MAC rather than assuming.
What this means for your income
Medicare rates are the floor of anesthesia economics; commercial contracts typically pay several times more per unit. A practice's payer mix therefore shapes revenue far more than production alone, which drives hospital stipends and group economics. If you are weighing independent work, model it with the group revenue calculator and read how anesthesia billing works.
Quick answers
Does Medicare pay CRNAs less than anesthesiologists?
No. For the anesthesia service, the fee schedule amount is the same. QZ and AA cases pay identically for the same procedure and time.
Can CRNAs bill Medicare in every state?
Yes. Direct billing rights are federal and nationwide. State scope of practice governs what services you may perform, and opt-out status affects facility supervision requirements only.
Do CRNAs have to accept Medicare assignment?
Yes. CRNAs must accept assignment, so the Medicare allowed amount is payment in full.
What about Medicare Advantage?
Medicare Advantage plans are commercial plans that must cover Part B services, but rates and rules come from your contract with each plan, which is why payer credentialing matters.
Sources
- CMS, Medicare Claims Processing Manual, Chapter 12, Section 140 (CRNA billing, assignment, 100 percent non-directed payment)
- ASA, CMS finalizes CY 2026 anesthesia conversion factors
- AANA, Fact Sheet Concerning State Opt-Outs (September 2026)
- 42 CFR 415.110, medically directed anesthesia services (eCFR)