Medicare pays the same fee schedule amount for an anesthesia case whether an anesthesiologist or a certified registered nurse anesthetist performs it alone. The two providers’ pay differs only when an anesthesiologist medically directs CRNAs across several rooms.
Medicare pays for anesthesia using base units set for each procedure, plus one time unit for every 15 minutes of anesthesia, multiplied by a conversion factor, under federal regulations. Time units are rounded to one decimal place. The 2026 national anesthesia conversion factor is $20.4976 for most clinicians, a 0.88% increase over 2025. For qualifying participants in advanced alternative payment models, it is $20.5998, according to Ventra Health. Local rates vary by geographic adjustment. CMS has proposed cutting both rates in 2027, to $20.2143 and $20.4165, respectively.
When an anesthesiologist medically directs two to four concurrent cases, Medicare pays the anesthesiologist 50% of the allowance for each case. The directed CRNA in each room receives the other 50%. To bill at that rate, the anesthesiologist must meet CMS medical direction requirements in each case. A CRNA working without medical direction is paid 100% under the physician fee schedule.
Medicare’s total payment per case does not change. But an anesthesiologist directing four rooms collects four half-fees, or twice what a single personally performed case pays.
Here is what the 2026 national rate works out to for four common ASC cases. The anesthesia times are illustrative examples, not CMS figures:
| Case (anesthesia code) | Base units | Example time | Full allowance (anesthesiologist or CRNA alone) | Each provider under medical direction | Anesthesiologist directing 4 such cases |
| Lumbar spine fusion (00670) | 13 | 180 min | $512.44 | $256.22 | $1,024.88 |
| Total knee replacement (01402) | 7 | 120 min | $307.46 | $153.73 | $614.93 |
| Colonoscopy (00811) | 4 | 30 min | $122.99 | $61.49 | $245.97 |
| Cataract surgery (00142) | 4 | 20 min | $108.64 | $54.32 | $217.27 |
After the Part B deductible, Medicare pays 80% of the allowance and the patient owes the remaining 20% as coinsurance.
Those fees are not keeping pace with what anesthesia staffing costs. The share of ASCs expecting to pay anesthesia stipends rose from 28% in 2024 to 44% in 2025, according to a VMG Health survey. Average professional anesthesia reimbursement fell 5.5% from 2019 to 2023, while the average CRNA salary rose from $181,040 in 2019 to $231,700 in 2024, according to Bureau of Labor Statistics data. Enhance Healthcare Consulting, which advises ASCs and anesthesia groups, said it sees more than 75% of ASCs nationwide requiring anesthesia financial support, according to an Aug. 26 sponsored article on Becker’s.
At the Becker’s 32nd Annual Meeting: The Business and Operations of ASCs, taking place October 29-31 in Chicago, ASC leaders, surgeons and healthcare executives will explore strategies to drive growth, enhance operational performance, navigate reimbursement challenges and prepare for the future of ambulatory surgery. Apply for complimentary registration now.
