Anesthesia services are reimbursed differently from other procedure codes. Part of the payment for anesthesia is based on 'base units,' which are assigned to anesthesia CPT codes by the Centers for Medicare & Medicaid Services (CMS). The remainder of the payment allowance is based on the time the patient was 'under anesthesia.' Both the base and time units are then multiplied by an anesthesia conversion factor (CF), which CMS releases annually and is specific to the locality where the anesthesia service is rendered.
The formula to calculate the allowed amount for anesthesia is:
(Base Units + Time (in units)) x CF = Anesthesia Fee Amt
A list of base units assigned to anesthesia CPT codes is available on the CMS Web site (PDF, 902 KB) in the Medicare Claims Processing Manual (Pub. 100-04), Chapter 12, section 50.K.
Reimbursement:
- Payment for services that meet the definition of 'personally performed' is based on the base units (as defined by CMS) and time, in increments of 15-minute units
- Services that are 'medically directed' are reimbursed at 50 percent of the 'personally performed' rate. Refer to the CMS Medicare Claims Processing Manual, chapter 12, sections 50.B-50.F for more information regarding the definitions of 'personally performed' and 'medically directed.'
- Payment for services that are 'medically supervised' is based on three base units per procedure with an additional unit of time if the physician documents that he or she was present at induction
Claim submission:
- Report actual anesthesia time in minutes on the claim
- Example: submit 17 minutes of anesthesia as '0017' in the units field (Item 24G of the CMS-1500 claim form) Carriers compute time units by dividing reported anesthesia time by 15 minutes (17 minutes = 1.13 units)
Reference: