CPT Codes 00100–00222: Anesthesia Billing, Coding & Reimbursement Guide for 2026

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CPT codes 00100–00222 cover anesthesia for procedures of the head — from salivary gland surgery through intracranial procedures. This is one of the highest-risk ranges in anesthesia coding: base units vary sharply between neighboring codes, some carry payer-specific coverage flags (ECT, eyelid work), and intracranial codes routinely intersect with qualifying circumstances and medical direction rules. Our anesthesia billing team at MedCloudMD built this reference for anesthesiologists, CRNAs, coders, and RCM leaders who need the code detail and the operational judgment behind it.

Key Takeaways

•     CPT 00100–00222 spans head anesthesia: salivary gland, eyelid, ear, eye, nose, intraoral, facial bone/skull, and intracranial procedures.

•     Base units differ by specific code, not just by body region — 00212 (subdural taps, 5 units) and 00216 (vascular procedures, 15 units) are both "intracranial" but far apart in value.

•     Payment = (base units + time units + qualifying circumstance units) × conversion factor, and the conversion factor varies by payer, locality, and provider arrangement.

•     The 2026 Medicare national anesthesia conversion factor is $20.5998 for Qualifying APM Participants and $20.4976 for other clinicians, per CMS's CY2026 final rule — up modestly from $20.3178 in 2025.

•     Medical direction, medical supervision, and personally performed anesthesia each carry different modifier and documentation requirements.

•     Documentation, not code selection alone, is what survives an audit — the two must be reviewed together.

Quick Answer: What Are CPT Codes 00100–00222?

CPT codes 00100–00222 are the anesthesia codes for procedures performed on the head, including salivary gland surgery, eyelid reconstruction, ear and eye procedures, nasal and sinus surgery, intraoral procedures, facial bone/skull surgery, and intracranial procedures. Correct selection depends on matching the anesthesia code to the surgical procedure actually performed — not simply the anatomical region — since base unit values can range from 4 units (e.g., otoscopy) to 15 units (intracranial vascular procedures) within the same broad category.

Complete CPT 00100–222 Reference

Base unit values below are drawn from CMS-aligned government fee schedules and are consistent across multiple published sources as of 2026. The authoritative source of record is the current ASA Relative Value Guide; always confirm current-year values and any payer-specific variation before billing.

CPT	Anesthesia For…	Base Units*	Coding Note
00100	Salivary gland procedures, incl. biopsy	5
00102	Plastic repair of cleft lip	6	Not for non-cleft lip repairs
00103	Reconstructive eyelid procedures (e.g., blepharoplasty)	5
00104	Electroconvulsive therapy (ECT)	4	Verify payer ECT coverage first
00120	Ear procedures, NOS	5
00124	Otoscopy	4	Unilateral service
00126	Tympanotomy	4	Unilateral service
00140	Eye procedures, NOS	5
00142	Lens surgery	4
00144	Corneal transplant	6
00145	Vitreoretinal surgery	6
00147	Iridectomy	4
00148	Ophthalmoscopy	4
00160	Nose/sinus procedures, NOS	5
00162	Radical nose/sinus surgery	7
00164	Biopsy, soft tissue of nose	4
00170	Intraoral procedures, NOS	5
00172	Repair of cleft palate	6
00174	Excision of retropharyngeal tumor	6
00176	Radical intraoral surgery	7
00190	Facial bone/skull procedures, NOS	5
00192	Radical facial bone/skull surgery (incl. prognathism)	7
00210	Intracranial procedures, NOS	11
00211	Craniotomy/craniectomy, evacuation of hematoma	10	Often trauma/emergent — check qualifying circumstance
00212	Subdural taps	5
00214	Burr holes, incl. ventriculography	9
00216	Intracranial vascular procedures	15	High-acuity — confirm time documentation
00218	Intracranial procedures, sitting position	13	Position itself doesn't change base CPT elsewhere
00220	Cerebrospinal fluid shunting procedures	10
00222	Electrocoagulation of intracranial nerve	6

How to Select the Correct Anesthesia CPT Code

•     Identify the surgical procedure actually performed, not just the body region.

•     Review the operative note and anesthesia record together — they should tell the same story.

•     Match the anesthesia service to the CPT descriptor that most specifically describes it (avoid defaulting to "not otherwise specified" codes when a specific code exists).

•     Confirm documentation supports medical necessity for that specific code.

•     Determine anesthesia start and stop time from the record, not an estimate.

•     Apply the correct provider-arrangement modifier (AA, QK, QX, QY, QZ) based on who actually performed or directed the case.

•     Check whether a qualifying circumstance applies and is documented.

•     Run a pre-submission quality review before the claim goes out.

Anesthesia Base Units, Explained

Base units reflect the relative complexity typically associated with a given service they do not include time. Two codes in the same body region can carry very different values, which is why 00218 (sitting position) carries more base units than 00212 (subdural taps) despite both being "intracranial." The ASA Relative Value Guide is the traditional source for base units, but it is not a universal payment guarantee — Medicare, Medicaid, and commercial payers each apply their own conversion factor and, in some cases, their own base unit table.

Illustrative Example — Not a Guaranteed Payer Payment

A 00210 case (11 base units) with 45 minutes of anesthesia time, billed personally performed, might be estimated as (11 base units + time units) × conversion factor. The actual time-unit conversion (e.g., per 15-minute increment) and the conversion factor itself both vary by payer and locality — this is a math illustration only, not a promised reimbursement.

Anesthesia Time Units

Anesthesia time begins when the anesthesia provider starts preparing the patient and ends when the provider is no longer personally in attendance. Time-unit conversion (how many minutes equal one unit) and rounding methodology are payer-specific — not universal so the same documented time can convert to different unit counts depending on the payer.

Anesthesia Modifiers

Modifier selection must reflect the actual provider arrangement and documented service — never select a modifier because it produces a higher reimbursement.

Medical Direction vs. Medical Supervision

Medical direction requires the anesthesiologist to meet specific documented involvement steps (pre-anesthesia evaluation, availability, and presence requirements) across no more than four concurrent procedures under Medicare rules. Medical supervision applies when direction requirements aren't met and is reimbursed differently. Personally performed anesthesia means the anesthesiologist provides the entire service without a medically directed CRNA. These distinctions are Medicare-specific; commercial payers may define concurrency differently, so confirm the applicable payer's policy before applying a modifier.

Qualifying Circumstances

Qualifying circumstance codes (99100, 99116, 99135, 99140) may be reported alongside the base anesthesia code for specific conditions — extreme age, hypothermia, controlled hypotension, or emergency conditions. Never add them automatically; each needs documentation that clearly supports the circumstance, and payer coverage of these add-on codes varies.

Physical Status Modifiers

P1 through P6 describe the patient's overall physical condition at the time of anesthesia, from a normal healthy patient (P1) to a declared brain-dead patient whose organs are being harvested (P6). Assignment must reflect the documented clinical condition — never assign a higher physical status based on age alone, and never assign it to increase reimbursement without clinical support.

Common Mistake

Assigning P3 or P4 by habit for older patients without documentation of the specific comorbidity that justifies it. Reviewers expect the anesthesia record to name the condition driving the physical status selection.

Billing Examples

Example 1 — Routine Ear Procedure

Tympanotomy is performed; 00126 is more specific than 00120 (NOS) and should be used since the exact procedure is documented. Checkpoint: 00120–00126 are unilateral by definition, so laterality doesn't change code choice.

Example 2 — Medically Directed CRNA, Intracranial Case

A CRNA provides anesthesia for a burr hole procedure (00214) while the anesthesiologist medically directs up to four concurrent cases. Modifier QX pairs with the anesthesiologist's QK claim; both records must independently support the direction steps — not just presence in the building.

Example 3 — Emergency Intracranial Case

A trauma patient needs emergent craniotomy for hematoma evacuation (00211). An emergency qualifying circumstance may apply if criteria and documentation support it — confirm rather than assume, and keep time and physical status documentation especially tight in compressed emergent records.

Common CPT 00100–222 Coding Errors

Error	Claim Impact	Prevention
Generic ("NOS") code used when a specific code exists	Downcoding or denial on audit	Match code to documented procedure, not habit
Time not clearly bounded	Under/overstated units	Standardize start/stop documentation
Modifier doesn't match provider arrangement	Denial or recoupment	Cross-check modifier against direction/supervision log
Physical status unsupported	Audit finding	Require documented justification for P3+
Qualifying circumstance added without support	Compliance risk	Require explicit documentation before adding

Denial Management

Denial Type	Root Cause	First Action
CPT mismatch	Code doesn't match operative note	Compare anesthesia and surgical documentation
Modifier denial	Direction/supervision criteria unmet or undocumented	Review concurrency and presence documentation
Medical necessity	Diagnosis doesn't support anesthesia service	Confirm diagnosis linkage before appeal
Bundling/NCCI	Edit pair conflict	Check current NCCI edits before resubmission

Pre-Billing Documentation Audit Checklist

☐   Correct patient and procedure

☐   Correct, most-specific anesthesia CPT selected

☐   Accurate start and stop time

☐   Pre- and post-anesthesia evaluation documented

☐   Provider identity and role verified

☐   Modifier matches documented provider arrangement

☐   Physical status supported by documented condition

☐   Qualifying circumstances supported, if reported

☐   Payer-specific requirements checked

AI-Assisted Anesthesia Coding

Modern tools can help with documentation review, code suggestions, missing-documentation alerts, modifier conflict detection, and denial prediction. But AI should assist qualified professionals rather than independently determine compliant coding decisions human review stays essential for medical necessity, modifier selection, and physical status assignment.

AI Use Case	Benefit	Required Human Review
CPT suggestions	Speeds initial code selection	Confirm against operative note
Time extraction	Reduces manual entry	Verify against source anesthesia record
Denial prediction	Flags high-risk claims pre-submission	Human decision on hold/submit

The 7-Point Anesthesia Revenue Integrity Review

•     CPT accuracy — does the code match the documented procedure?

•     Time accuracy — are start/stop times clean and defensible?

•     Modifier accuracy — does it reflect the real provider arrangement?

•     Documentation completeness — pre- and post-anesthesia notes present?

•     Qualifying circumstance capture — supported and not over- or under-reported?

•     Denial recovery — are denials worked, not written off?

•     Underpayment detection — are paid claims checked against expected units?

Anesthesia Revenue KPIs to Track

KPI	What It Signals When It Worsens
Clean Claim Rate	Coding or documentation process breakdown
Denial Rate	Rising payer scrutiny or internal errors
Days in AR	Slower payer response or weak follow-up
Coding Accuracy	Training gap or unclear documentation
Underpayment Rate	Contracted rate not being verified against payment

We don't publish universal benchmarks — track your own trend line by procedure family and payer, since acceptable ranges vary by contract and case mix.

2026 Medicare Anesthesia Payment Snapshot

CMS's CY2026 Physician Fee Schedule final rule set the national anesthesia conversion factor at $20.5998 for Qualifying APM Participants and $20.4976 for other clinicians both up modestly from $20.3178 in 2025, per CMS and ASA's published analysis. These are Medicare national figures; Medicaid and commercial payers set their own conversion factors and sometimes their own base-unit tables, so verify by payer and locality rather than assuming the Medicare figure applies universally.

Audit Frequency Recommendation

Well-run anesthesia groups typically combine monthly spot checks on high-volume codes, quarterly focused audits on high-risk families like the intracranial range, and trigger-based audits after a payer policy change, new CRNA onboarding, or a denial spike — rather than relying on one annual review.

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