Anesthesia Modifiers (QY, QK, AD, AA)
HCPCS modifiers identifying the anesthesia care team's involvement in a procedure.
1 min read · Last reviewed May 23, 2026
At a glance
- Category
- Billing
- Primary sources
- 1
- Workspace handoff
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Where this comes up
This shows up in revenue-cycle work — claim scrubbing, charge entry, posting, A/R follow-up, and month-end close. Billers and practice managers hit this term when reconciling a payment, working a denial queue, or auditing why a claim aged past 60 days.
Full definition
What it is in practice
CMS recognizes AA (anesthesiologist personally performed), QY (medical direction of one CRNA), QK (medical direction of 2-4), AD (supervising more than 4). Payment differs by modifier.
How it shows up in your practice
Use the right modifier per encounter. Documentation must support the level of involvement claimed.
Sources
- CMS — Modifier Referencehttps://www.cms.gov/medicare/coding-billing/modifiers
Confirm anesthesia modifier use in Ask D3
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D3rx is a healthcare-billing and compliance research aid maintained by D3rx Inc. Articles are drafted by an LLM (Anthropic Claude) against primary HHS, OCR, CMS, eCFR, NIST, and state-regulator publications, and reviewed for restraint and source fidelity by the D3rx team.
Reviewer status: a named credentialed reviewer (CHC, CHPC, or healthcare attorney) is being engaged. Until that engagement is finalized, this page does not claim credentialed review.
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This glossary entry is a research aid for billing and compliance staff. It does not provide legal, medical, or financial advice and does not replace counsel. References cited link to primary sources at HHS, OCR, CMS, eCFR, NIST, and the relevant payer or industry body.