US · guidance
CMS Pub. 100-04, ch. 12, § 140.3.3
Billing Modifiers
The following modifiers are used by qualified nonphysician anesthetists when
billing for anesthesia services:
• QX – Qualified nonphysician anesthetist service: With medical direction by a
physician.
• QZ – CRNA service: Without medical direction by a physician.
• QS – Monitored anesthesia care services
• NOTE: The QS modifier can be used by a physician or a qualified nonphysician
anesthetist and is for informational purposes. Providers must report actual
anesthesia time and one of the payment modifiers on the claim.
History
(Rev. 3747; Issued: 04-14-17; Effective: 01-01-17; Implementation: 05-15-17)
Provenance
- Source
- cms.gov
- Retrieved
- 2026-08-25
- Edition
- iom-2026-08-25
- Content hash
4002a16b263c5df5ec386bbd87956fd451481ff6866ee6dc4eb999f635c8a22a
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