Crystal's MCW Coder Hub⚕️ Modifier -AA: Anesthesia Services Personally Performed by Anesthesiologist
Short Definition
The anesthesia service was personally and fully performed by the anesthesiologist throughout the entire procedure — from pre-anesthesia evaluation through emergence and post-anesthesia care.
Long Definition
Modifier -AA is a HCPCS Level II anesthesia payment modifier reported by a physician anesthesiologist (MD or DO) to indicate they personally performed the entire anesthesia service for the patient. No CRNA, anesthesiologist assistant (AA), or other qualified nonphysician anesthetist was involved in providing the anesthesia care. The anesthesiologist was present and personally managed all phases of the anesthetic.
This modifier is the highest-level anesthesia payment modifier and results in reimbursement at 100% of the applicable anesthesia fee schedule allowable. It is the modifier used when an anesthesiologist is doing their own case start to finish, without concurrent direction of other providers.
Who Reports Modifier AA
- Physician anesthesiologist (MD or DO) only.
- CRNAs and anesthesiologist assistants do not use modifier -AA — they use -QX or -QZ.
- This modifier is physician-only.
When to Use
- The anesthesiologist personally performed all anesthesia services for the patient.
- No CRNA, AA, or other qualified nonphysician anesthetist was involved.
- The anesthesiologist was present for the entire anesthetic, including:
- Pre-anesthesia evaluation and preparation.
- Anesthesia induction.
- Maintenance of anesthesia throughout the procedure.
- Emergence.
- Post-anesthesia evaluation and care.
When NOT to Use
- When the anesthesiologist is medically directing 2-4 concurrent cases — use -QK instead.
- When the anesthesiologist is medically directing one CRNA — use -QY instead.
- When the anesthesiologist is medically supervising more than 4 concurrent cases — use -AD instead.
- Never report -AA on the same claim line as -QK, -QX, -QY, -QZ, or AD — these modifiers are mutually exclusive.
Reimbursement
- Billed at 100% of the anesthesia fee schedule allowable.
- Calculated as: (Base Units + Time Units + Modifying Units) × Conversion Factor = Allowable.
- No payment split required — the anesthesiologist retains the full allowable.
Anesthesia Payment Modifier Family — Quick Reference
| Modifier | Reported By | Scenario | Rate |
|---|---|---|---|
| -AA | Anesthesiologist | Personally performed, full case | 100% |
| -QK | Anesthesiologist | Medically directing 2-4 concurrent cases | 50% |
| -QY | Anesthesiologist | Medically directing 1 CRNA | 50% |
| -AD | Anesthesiologist | Supervising 5+ concurrent cases | Limited base units only |
| -QX | CRNA / AA | Medically directed by a physician | 50% |
| -QZ | CRNA | Without medical direction by a physician | 100% CRNA rate |
Quick Example
- Anesthesiologist Dr. A personally performs all anesthesia services for a total hip arthroplasty (CPT 01214).
- No CRNA or AA is involved.
- Dr. A bills: 01214 -AA under their own NPI.
- Reimbursement: full anesthesia allowable for that CPT code.