Anesthesiology Billing & Coding Guide
ASA crosswalk, base + time + modifier units, monitored anesthesia care, regional blocks.
Common Anesthesiology CPT Codes
Ranked by claim frequency, with current MPFS work RVUs and global periods.
| Code | Description | Work RVU | Total RVU | Global |
|---|---|---|---|---|
| 00100 | Anes px salivary gland w/bx | 0.00 | 0.00 | XXX |
| 00102 | Anes px plstc rpr cleft lip | 0.00 | 0.00 | XXX |
| 00103 | Anes rcnstv px eyelid | 0.00 | 0.00 | XXX |
| 00104 | Anes electroconvulsive ther | 0.00 | 0.00 | XXX |
| 00120 | Anes px ear w/bx nos | 0.00 | 0.00 | XXX |
| 00126 | Anes px ear tympanotomy | 0.00 | 0.00 | XXX |
| 00140 | Anes procedures on eye nos | 0.00 | 0.00 | XXX |
| 00142 | Anes px on eye lens surgery | 0.00 | 0.00 | XXX |
| 00144 | Anes px eye corneal trnspl | 0.00 | 0.00 | XXX |
| 00145 | Anes px eye vitreortnl surg | 0.00 | 0.00 | XXX |
| 00147 | Anes px on eye iridectomy | 0.00 | 0.00 | XXX |
| 00148 | Anes px eye ophthalmoscopy | 0.00 | 0.00 | XXX |
| 00160 | Anes px nose&sinus nos | 0.00 | 0.00 | XXX |
| 00162 | Anes px nose&sinus rad surg | 0.00 | 0.00 | XXX |
| 00164 | Anes px nose&sins bx sft tis | 0.00 | 0.00 | XXX |
| 00170 | Anes intraoral px nos | 0.00 | 0.00 | XXX |
| 00172 | Anes ntroral px rpr clft pal | 0.00 | 0.00 | XXX |
| 00174 | Anes ntrorl exc rtrphrng tum | 0.00 | 0.00 | XXX |
| 00176 | Anes intraoral px rad surg | 0.00 | 0.00 | XXX |
| 00190 | Anes px facial b1/skull nos | 0.00 | 0.00 | XXX |
What Anesthesiology practices are leaving on the table
High-value services that consistently get under-billed across the specialty. Each one is rooted in current 2026 fee schedule and policy updates.
Undersell of modifier 51 on multiple simultaneous procedures. Example: ear biopsy + tympanotomy (00120 + 00126-51) generates $85-120 additional RVU vs. bundling into single code. Workflow fix: require operative report template flagging 'Secondary Procedure Y/N' and trigger modifier 51 attachment rule.
Failure to capture distinct anesthesia for combined eye procedures. Example: cataract + vitreoretinal (00142 + 00145) versus single 00145 claims up to $210 additional revenue annually per 3-4 such cases. Fix: ophthalmology operative templates must list 'Anterior Segment', 'Posterior Segment', or 'Both' to auto-trigger dual coding.
Underbilling neuraxial labor anesthesia due to modifier confusion. 01967 + epidural during vaginal delivery often downgraded to basic anesthesia instead of neuraxial level. Impact: $150-300 per case, 5-10 cases monthly in OB practices. Fix: labor & delivery anesthesia record must document 'epidural placement time', 'dosing intervals', and 'delivery method' to enforce neuraxial code selection.
Missing modifier 58 for planned staged eye procedures. Cataract surgery on right eye, then left eye 2-3 days later often billed as new procedure without modifier 58, triggering global period bundling rules. Impact: $120-180 per second eye. Fix: surgical scheduler flag for 'bilateral staged' cases and auto-append modifier 58 to second claim.
Code pairs that auto-bundle to CO-97
From the National Correct Coding Initiative for Anesthesiology. The rationale tells you when a modifier legitimately bypasses the edit and when it cannot.
Lens surgery and vitreoretinal surgery on same eye bundle unless distinctly separate anatomical zones documented (e.g., anterior vs. posterior segment pathology requiring separate operative entry). Modifier 59 with detailed operative note showing two separate surgical fields justifies separation.
Reconstructive breast and radical/modified breast both address same surgical field. Only one anesthesia code reports unless documented as staged procedures on different dates. Modifier 58 or 59 requires clear temporal or anatomical separation.
Tympanotomy is more specific than ear biopsy NOS. Report only the specific code unless multiple distinct ear procedures occur (e.g., tympanotomy plus external ear biopsy). Modifier 51 applies if truly separate procedures.
Central venous access and CVDF insertion both address same vascular access event. Report insertion code (00534) if new placement; access code (00532) if existing line manipulation. Bundling without modifier documentation triggers RAC downgrades.
Modifier Guidance for Anesthesiology
When each modifier legitimately applies in this specialty, with denial-pattern context and audit-defense documentation.
Modifier 25 is rarely appropriate in Anesthesiology because anesthesia codes carry XXX global status (no postoperative period). Use only if anesthesiologist performs distinct E/M (e.g., complex preoperative clearance or separate pain management consultation) on same DOS. Example: 00142 (cataract anesthesia) + 99214-25 (separate preop E/M for cardiac risk stratification).
Modifier 59 separates bundled codes when documentation shows distinct operative fields, different anatomical structures, or separate operative sessions. In Anesthesiology, apply to justify multiple anesthesia codes (e.g., 00142 and 00145 if anterior and posterior eye surgery) only with separate operative notes and time documentation.
Modifier 51 applies when multiple distinct surgical procedures occur requiring separate anesthesia planning. Example: 00120 (ear biopsy) + 00126 (tympanotomy) on same patient, same date. Requires detailed operative report showing both procedures performed.
Use LT/RT to specify laterality when bilateral procedures occur on same date but billed separately. Example: 00142-LT and 00142-RT for cataract anesthesia on both eyes. Required for claim clarity; omission triggers bundling to single bilateral code.
Modifier 58 indicates staged procedure during postoperative period. Apply when follow-up anesthesia service occurs within postop window for planned continuation of treatment (e.g., second eye cataract surgery 48 hours after first). Requires operative plan documentation from primary surgeon.
Documentation requirements
What needs to live in the encounter note for these codes to survive a payer audit.
- Operative start/stop times for each CPT code to establish distinct procedure duration and justify multiple anesthesia codes without bundling denial.
- Surgeon's operative note identifying primary and secondary procedures with distinct anatomical regions or approaches to support modifier 59 or 51 claims.
- Patient's medical complexity (ASA class, comorbidities, airway difficulty) to establish medical necessity for specific anesthesia codes and defend against denial for 'routine' services.
- Anesthesia record with type of anesthesia (general, regional, monitored care) and any unusual complications or extended time to defend against payment reductions.
- Preoperative assessment documenting baseline functional status and specific anesthetic risk factors to justify higher acuity codes if claimed (e.g., neuraxial vs. general).
- Laterality confirmation (left vs. right) for bilateral codes or separate code reporting to prevent automatic bundling into single bilateral code.
OIG and audit triggers in Anesthesiology
Patterns that show up in OIG Work Plans, RAC audits, and CERT improper payment reviews. Build internal compliance checks around these.
OIG Work Plan historically targets Anesthesiology for inappropriate bilateral modifier application. Risk: billing 00402 and 00402-50 or bilateral modifier when only unilateral breast surgery occurred. Defense: operative report documenting mirror-image incisions and separate surgical fields on both sides, with explicit bilateral indication from surgeon.
RAC pattern: Multiple anesthesia codes bundled into single code due to missing modifier 59 documentation. Risk: claiming 00142 and 00145 on same claim without distinct operative notes showing anterior and posterior segment pathology. Defense: separate anesthesia records, detailed surgical plan stating 'combined anterior-posterior approach with distinct anesthetic considerations for each phase'.
CMS scrutiny on neuraxial codes (01967, 01968) for obstetric services: overstating complexity or billing both when only one applies. Risk: claiming both vaginal delivery neuraxial anesthesia and cesarean anesthesia when patient had planned repeat cesarean only. Defense: operative timeline, delivery method documentation, anesthesia record showing single anesthetic event.
Commercial payer audits flagging Central Venous Access (00532) and CVDF Insertion (00534) as medically unnecessary when existing central line present. Risk: billing access code for routine existing line maintenance. Defense: operative note documenting new line placement rationale (failed prior access, infection, thrombosis) and physician signature confirming medical need.
Payer-specific billing notes
Where the major payers diverge from generic Medicare rules in Anesthesiology.
ME Medicare +
CMS National Coverage Determination 150.2 covers anesthesia for covered surgical procedures; Local Coverage Determinations (LCDs) vary by MAC region. Neuraxial obstetric anesthesia (01967, 01968) requires labor/delivery documentation; no prior auth needed but claims audited heavily for appropriate complexity level. 2026 focus: stricter bundling enforcement for combined anterior/posterior eye procedures; expect denials on modifier 59 without detailed operative notes. Bilateral modifier appended to anesthesia codes only when distinct bilateral surgical incisions documented.
UN UnitedHealthcare +
Optum delegates most Anesthesiology precert to local anesthesia programs; prior authorization required for complex intracranial, cardiac, and thoracic procedures. Medical policy MA-1017 limits multiple anesthesia codes to 'distinct operative phases' and requires operative report submission. Denies modifier 51 on anesthesia codes without explicit secondary procedure documentation. Neuraxial codes require 'procedure type: epidural, spinal, combined' notation in claim remarks.
AN Anthem +
Anthem uses RxCare (not eviCore) for some anesthesia precert; most coverage follows Medicare LCD rules by region. Medical Policy ANT-C-2021-004 bundles anesthesia codes for 'same anatomical region on same date' without modifier 59 substantiation. Prior auth not typically required but claims for multiple codes audited at 15% rate. Modifier 50 for bilateral procedures must have bilateral operative note or claim downgrades to single code.
CI Cigna +
Cigna eviCore handles precert only for certain intracranial and cardiovascular procedures; most Anesthesiology claims process without prior auth. Medical policy enforces strict bundling per NCCI guidelines; modifier 59 requires 'medically appropriate documentation of distinct services'. Denies claims with modifier 59 if operative note does not explicitly describe separate anatomical approaches or distinct operative phases. Cigna pays 5-8% below Medicare rates; bundling denials result in total loss, not reduction.
Standard Anesthesiology coding workflow
Step 1: Abstract surgical procedure(s) from operative report and map to primary CPT; identify secondary procedures in separate anatomical zones or distinct operative phases. Step 2: Document operative times, anesthetic approach (general/regional/local), and patient ASA class in anesthesia record. Step 3: Determine if procedures bundle under NCCI or payer rules; if separation needed, confirm modifier 59 or 51 and dual operative notes exist. Step 4: Verify ICD-10 primary diagnosis supports medical necessity for anesthesia level billed. Step 5: Audit modifier placement (LT/RT for laterality, 58 for staged) and submit with operative note attachments for complex cases.
Get the full PayerReady toolkit
Credentialing + billing/coding tools built for Anesthesiology, free access with enrollment.
Start free →Run this code through our claim audit tool
Check NCCI bundling, MUE limits, and modifier logic before submission.
Try the auditor →Verified against CMS 2026 code set, current NCCI Quarterly Updates, and the X12 Claim Adjustment Reason Code reference. Last updated April 15, 2026. See data sources and methodology.
Did this page help?
Quick signal so we know what to improve.
If you want a code reference page that doesn't exist yet, email coding@payerready.com.
Tell us what's missing or wrong: coding@payerready.com. We respond within 5 business days.
Reviewed by the PayerReady Medical Coding Team
Verified against the CMS 2026 code set on May 31, 2026.
Powered by 11K CPT · 98K ICD-10 · 860K MPFS rates · 4.5M NCCI edits · 9.5M NPIs. Our data methodology · About our coding team