The main modifiers
| Modifier | Meaning |
|---|---|
| QZ | CRNA service without medical direction by a physician |
| QX | CRNA service with medical direction by a physician |
| AA | Anesthesia services performed personally by an anesthesiologist |
| QY | Medical direction of one CRNA by an anesthesiologist |
| QK | Medical direction of two, three or four concurrent anesthesia procedures |
| AD | Medical supervision by a physician of more than four concurrent procedures |
How Medicare splits payment
When a CRNA works without medical direction (QZ), the CRNA can be paid the full anesthesia fee. When an anesthesiologist medically directs the CRNA (QY or QK for the physician, QX for the CRNA), Medicare generally splits the fee, paying each about half.
Why it matters
Medical direction has specific requirements the anesthesiologist must meet and document for each case. If the staffing, the documentation and the modifiers don't match, claims can be underpaid, denied or later recovered in an audit.
This article is general information, not billing, legal or tax advice. Payer rules change; always check current guidance.
Sources
Free checklist
Medical Direction Documentation Checklist
The seven requirements an anesthesiologist must meet and document for each medically directed case.
Download free