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Billing, Coding + CRNA Scope of Practice
TEXTProfessional Practice · 7 min read
The non-clinical side of practice that drives the business. Base units, time units, medical direction vs supervision, opt-out states.
After this lesson you can
2 min read7 sections- Apply base units + time units + modifying units.
- Distinguish QZ vs QX vs AA modifiers.
- Document for billing compliance.
- Understand TEFRA + medical-direction rules.
Anesthesia billing fundamentals
Anesthesia charges = (Base Units + Time Units + Modifying Units) × conversion factorBase units assigned per CPT code (e.g., CABG = 25, knee arthroscopy = 4, central line = 5).
Time units = each 15 min (or 12 min for some payers) of anesthesia care from start of preparation to handoff in PACU.
Modifying units for ASA physical status (P3=+1, P4=+2, P5=+3, emergent +2).
Conversion factor varies by payer.
Medical direction vs medical supervision
Medicare TEFRA 7-step medical direction: anesthesiologist must (1) perform preanesthetic exam, (2) prescribe anesthesia plan, (3) personally participate in most demanding procedures (induction + emergence), (4) ensure qualified individual performs non-personally-performed parts, (5) monitor course at frequent intervals, (6) remain physically present + available for emergencies, (7) provide indicated postanesthesia care.
Pay split: anesthesiologist 50%, CRNA 50%.
Concurrent medical direction limit: 4 rooms.
Medical supervision (>4 rooms or steps not met): different + lower payment formula.
Non-medically-directed CRNA practice
Bills at 100% of anesthesia fee schedule (not split). ~24 opt-out states have opted out of CMS physician-supervision requirement for CRNAs in hospitals/ASCs (varies; check current AANA list).
Independent CRNA practice common in rural America + military/VA.
Scope of practice defined by state board of nursing + AANA standards.
Key CPT/HCPCS modifiers
QY — anesthesiologist medically directs 1 CRNA.
QK — anesthesiologist medically directs 2-4 concurrent.
QX — CRNA service with medical direction.
QZ — CRNA service without medical direction.
AD — anesthesiologist supervises >4 procedures.
P modifiers — ASA physical status.
23 — unusual anesthesia.
47 — anesthesia by surgeon (rare).
CRNA scope of practice
- prescriptive authority
- signing privileges (death certificates, IV access for non-CRNAs)
- independence in supervision
AANA Standards for Nurse Anesthesia Practice + Code of Ethics drive professional accountability.
Practice models
All-CRNA practice — common in rural + critical access hospitals.
Anesthesiologist-only — rare in modern practice.
Mixed models — concurrent ACT for complex + CRNA-only for routine.
Payment + outcomes data: meta-analyses (Lewin, RAND) show comparable outcomes across models for matched case complexity; cost-effectiveness favors CRNA-led care.
Pre-anesthesia + post-anesthesia documentation
- history
- physical
- ASA class
- anesthesia plan
- informed consent
- drugs
- doses
- times
- vital signs q5 min minimum
- fluids
- blood products
- events
- vital signs
- level of consciousness
- pain
- nausea
- PACU discharge criteria met
Electronic anesthesia record (EAR) standard in most large hospitals — AIMS systems.
⚠ Common pitfalls
- Documenting time imprecisely — start time = anesthesia care, end = transfer of care.
- Confusing QZ (CRNA alone) with QX (medically directed) — different reimbursement.
- Missing pre-procedure note requirements for TEFRA — affects billing.
- Treating coding as 'someone else's problem' — affects practice viability.
💎 Clinical pearls
- Base units: ASA assigns each procedure; time units typically 1 unit per 15 min.
- TEFRA 7 steps for medical direction: pre-eval, plan, induction, monitoring, emergence, periop, documentation.
- QZ: CRNA non-medically-directed (full reimbursement).
- QX: CRNA medically directed by anesthesiologist — split-billing situation.
Recap
- Base units: ASA assigns each procedure; time units typically 1 unit per 15 min.
- TEFRA 7 steps for medical direction: pre-eval, plan, induction, monitoring, emergence, periop, documentation.
- QZ: CRNA non-medically-directed (full reimbursement).
- QX: CRNA medically directed by anesthesiologist — split-billing situation.
Mark each section done to complete the module.