Anesthesia billing turns your anesthesia record into a claim, sends it to an insurance payer, and collects payment weeks or months later. Payment is based on base units, time units, and a conversion factor, not a flat fee per case.
If you are a W-2 CRNA, someone else handles all of this. If you are a 1099 CRNA, a group owner, or thinking about starting a group, the billing process is your revenue. Here is the whole lifecycle.
Key points
- Payment = (base + time + modifying units) x conversion factor.
- Your anesthesia record is the source document for every claim.
- Wrong modifiers and overlapping times are the classic failure points.
- Billing companies typically charge 4 to 8 percent of collections.
The anesthesia payment formula
Almost every payer uses the same structure:
(Base units + time units + modifying units) x conversion factor = payment
Base units come from the anesthesia CPT code for the procedure. Time units are the minutes you personally provided care, usually divided by 15. The conversion factor is a dollar amount per unit that varies by payer. Medicare's 2026 national rate is $20.4976 per unit; commercial payers often pay $60 to $100 or more.
For a full walkthrough with a worked example, see anesthesia base units and time units.
The claim lifecycle, step by step
1. The case happens and you document it
The anesthesia record is the source document for the claim. Start time, stop time, the procedure, who provided care, and any modifiers all come from it. Sloppy times or a missing signature can delay or shrink payment months later.
2. Charge capture and coding
A coder (or billing software) assigns the anesthesia CPT code, the ICD-10 diagnosis codes, the anesthesia modifier (such as QZ for non-medically directed CRNA care), and any physical status or qualifying circumstance codes. The modifier tells the payer who delivered the care and how to split payment. See the QZ modifier and medical direction vs supervision.
3. The claim is created and scrubbed
The biller builds a claim (electronic format called an 837P for professional services) and runs it through edits: valid codes, matching patient data, correct provider numbers. Claims that fail edits get fixed before they go out.
4. The clearinghouse
Most claims do not go straight to the payer. They pass through a clearinghouse, a middleman that checks formatting, routes the claim to the right payer, and returns acceptance or rejection reports. A rejection here never reached the payer, so it does not count as a denial. It just needs to be corrected and resent.
5. Payer adjudication
The payer checks eligibility, medical necessity, and your enrollment status, then prices the claim. For Medicare this is the fee schedule amount. For commercial payers it is your contracted rate, or a much lower out-of-network calculation if you are not contracted. This is why credentialing and payer enrollment matter before you work.
6. Payment and the remittance
The payer sends payment plus an electronic remittance advice (ERA or 835) explaining what was paid, adjusted, or denied. Medicare pays 80 percent of the allowed amount; the patient or a secondary plan owes the rest.
7. Patient billing and follow-up
Deductibles, coinsurance, and copays get billed to the patient. Denied or underpaid claims go to follow-up: corrections, appeals, or resubmission. This back-end work is where a lot of revenue is won or lost.
Who the players are
| Player | What they do |
|---|---|
| You (the provider) | Deliver care, document times and modifiers accurately |
| Coder | Assigns CPT, ICD-10, and modifiers from the record |
| Biller or billing company | Builds claims, works denials, posts payments |
| Clearinghouse | Formats, routes, and pre-checks claims |
| Payer | Adjudicates and pays (Medicare, Medicaid, commercial) |
| Patient | Owes deductibles, coinsurance, copays |
Billing companies for anesthesia typically charge a percentage of collections, commonly in the 4 to 8 percent range, though rates vary with volume and services. Some groups bill in-house instead.
What can go wrong
- Missing or overlapping anesthesia times. Payers audit time units, and concurrency conflicts (two cases with overlapping times under one provider) trigger denials.
- Wrong modifier. Billing QX when the case was actually non-medically directed QZ changes who gets paid and how much.
- Not enrolled or not credentialed. Claims for dates before your effective date usually deny. See Medicare enrollment.
- Eligibility surprises. The patient's coverage lapsed or the payer on file is wrong.
- Timely filing. Every payer has a deadline, often 90 days to one year from the date of service. Miss it and the claim is dead.
- Underpayment nobody catches. Payment posted at the wrong contracted rate, never appealed.
Why CRNAs should care even as employees
Your production is measured in units. Understanding how units and modifiers work helps you read productivity reports, evaluate job offers with unit-based bonuses, and negotiate from facts. If you ever go independent, this knowledge is the difference between collecting what you earned and leaving it on the table. Try the CRNA group revenue calculator to see how units translate to dollars.
How long does it take to get paid?
Clean electronic claims to Medicare generally pay in about 14 to 30 days. Commercial payers vary; 30 to 60 days is common for clean claims, and denied claims can stretch to months.
Do CRNAs bill under their own name?
Yes, when they enroll with payers under their own NPI. CRNAs have been able to bill Medicare directly since 1989. In employed settings, the employer usually bills under a group number with your NPI as the rendering provider.
What percentage of charges actually gets collected?
It depends entirely on payer mix and contracted rates. Charges are list prices; collections reflect fee schedules and contracts. Judge a billing operation by collections per unit, days in accounts receivable, and denial rate, not by charges.