CPT code 00326 describes anesthesia services provided for all procedures on the larynx and trachea in children younger than one year of age. It is an age-restricted, site-specific anesthesia code used exclusively in pediatric cases where the patient is an infant — defined as less than 12 months old on the date of the procedure. The code carries 7 base units under the CMS anesthesia base unit schedule, reflecting the heightened complexity and specialized monitoring demands of neonatal and infant airway anesthesia management.
What Does CPT Code 00326 Mean?
CPT 00326 identifies general or regional anesthesia administered by a qualified anesthesia provider — an anesthesiologist, certified registered nurse anesthetist (CRNA), or anesthesia assistant (AA) — for any surgical or diagnostic intervention involving the larynx or trachea in a patient who has not yet reached their first birthday. The code is categorized under Anesthesia for Procedures on the Neck in the AMA CPT code set.
Key attributes of CPT 00326:
- Billable status: Active; valid for claims in 2025 and 2026 with no descriptor changes
- Patient eligibility: Strictly limited to infants younger than 1 year of age at the time of surgery
- Anatomical site: Larynx and trachea only (not broader neck structures)
- Service category: Anesthesia — not a surgical or procedural code
- Provider type: Anesthesiologist, CRNA, or AA; may be billed under various provider modifiers
- Applicable setting: Hospital inpatient (POS 21), hospital outpatient (POS 22), and ambulatory surgical center (POS 24)
What Procedures Does CPT 00326 Cover?
CPT 00326 functions as a “global” anesthesia code for the larynx and trachea in infants — meaning it applies regardless of which specific surgical or diagnostic procedure is being performed in that anatomical region, as long as the patient is under 1 year of age. Common procedures that trigger this anesthesia code include:
- Direct laryngoscopy (diagnostic or operative) in infants — e.g., for evaluation of stridor or subglottic stenosis
- Microlaryngoscopy with or without laser ablation of subglottic lesions
- Laryngeal papillomatosis excision via direct scope
- Tracheoscopy and bronchoscopic evaluation of the proximal trachea in neonates
- Tracheotomy (tracheostomy) performed in infants under 12 months
- Endoscopic foreign body removal from the larynx or proximal trachea
- Subglottiscopy for evaluation of congenital airway anomalies
- Tracheal dilation for congenital tracheal stenosis
In practice, anesthesia coders frequently encounter 00326 when a pediatric ENT or pulmonologist performs a scope procedure on a premature infant or neonate with a congenital airway abnormality. These cases are almost always performed in a hospital inpatient or outpatient surgical setting, rarely in a freestanding ASC, due to the risk profile of this patient population.
What Does CPT 00326 Specifically Exclude?
CPT 00326 does not cover:
- Anesthesia for larynx or trachea procedures in patients who are 1 year of age or older (use CPT 00320 instead)
- Anesthesia for esophageal or thyroid procedures in infants (the larynx/trachea site restriction is specific)
- Anesthesia for tracheobronchial procedures deeper in the thorax (consider intrathoracic anesthesia codes)
- Anesthesia for intubation-only without a separate surgical procedure being performed — airway management is a component of anesthesia care and not separately reportable
- The surgical laryngoscopy or tracheoscopy procedure itself — the procedural CPT code (e.g., 31515, 31520) is reported by the operating surgeon and is never bundled into the anesthesia claim
When Is CPT 00326 the Right Code to Use?
Correct selection of CPT 00326 requires satisfying every one of the following criteria simultaneously:
- Confirm the patient’s age is less than 1 year. The anesthesia record, operative report, and demographic data must all align. The patient must be younger than 12 months on the date the anesthesia was administered — not the date of scheduling or consent.
- Confirm the anatomical site is the larynx or trachea. If the primary surgical target involves the esophagus, thyroid, or neck lymphatics, the correct anesthesia code for patients under 1 year requires clinical judgment and crosswalk review (see below).
- Confirm a separate surgical or diagnostic procedure is being performed. CPT 00326 is not used for anesthesia standby or monitoring-only services without a concurrent procedure.
- Identify the highest base unit code if multiple procedures occur. Per standard anesthesia billing rules, when more than one surgical procedure is performed under a single anesthesia, only the anesthesia code with the highest base unit value is reported — but total time encompasses all procedures.
- Select the appropriate provider and physical status modifiers. These are added to the base 00326 claim and do not change the code itself.
- Determine whether qualifying circumstance add-on codes apply — with a critical exception unique to this code (see below in the reimbursement section).
How Does CPT 00326 Differ From CPT 00320?
The most common confusion in this code family is between 00326 and 00320. Here is the precise distinction:
| Factor | CPT 00326 | CPT 00320 |
|---|---|---|
| Patient age | Younger than 1 year | 1 year of age or older |
| Anatomical scope | Larynx and trachea only | Esophagus, thyroid, larynx, trachea, neck lymphatics |
| Base units (CMS) | 7 | 6 |
| Add-on code +99100 | Do NOT report separately | May be applicable (age >70) |
| Descriptor specificity | Age-restricted, site-restricted | Age-restricted, broader site scope |
| Typical patient | Neonate or young infant | Child, adult, or elderly patient |
The one-base-unit difference between 00326 (7 BU) and 00320 (6 BU) reflects CMS’s recognition that infant anesthesia for laryngeal and tracheal procedures is inherently more complex. Selecting 00320 for an infant — even inadvertently — results in a one-unit underpayment on every claim for this code category.
What Documentation Is Required to Support CPT 00326?
Because CPT 00326 is age-specific, documentation errors in this code carry a particularly high audit risk. The patient’s age is a billing criterion, not just a clinical fact — which means payers can deny or recoup the claim if documentation is insufficient to establish it.
What Must the Provider Document in the Anesthesia Record and Clinical Notes?
The following elements are required to support a compliant CPT 00326 claim:
- Patient date of birth — must appear on the anesthesia record and reconcile with the claim’s date of service to confirm the patient was under 12 months old
- Procedure start and end time for anesthesia — required to calculate anesthesia time units (each 15-minute increment = 1 time unit for most payers)
- The specific surgical procedure performed — documented in the operative report by the surgeon, allowing the anesthesia coder to crosswalk the surgical CPT to the correct anesthesia code
- Anesthesia type — general anesthesia is standard for this patient population; the record should note induction method and agents used
- Monitoring and hemodynamic data — continuous documentation of vital signs, oxygen saturation, end-tidal CO₂, and airway management events throughout the case
- Physical status classification — the ASA physical status (P1 through P6) must be documented and reflected in the modifier attached to the claim
- Provider identity and role — medical direction, supervision, or independent CRNA service must be documented to support the correct billing modifier (AA, QK, QX, QZ, etc.)
- Pre-anesthesia assessment and post-anesthesia evaluation notes — required for complete anesthesia care documentation under both CMS Medicare Claims Processing Manual, Chapter 12 and most commercial payer policies
What Are the Documentation Standards for Facility vs. Non-Facility Settings?
| Documentation Element | Hospital (Facility) Setting | ASC (Non-Facility) Setting |
|---|---|---|
| Patient age verification | Part of admission records | Must be in pre-op assessment |
| Anesthesia record | Maintained by facility and anesthesia provider | Maintained by anesthesia provider |
| Surgical report linkage | Part of integrated chart | Surgeon’s op note must be available |
| Physical status documentation | In pre-anesthesia eval | In pre-anesthesia eval |
| Time documentation | Continuous intraoperative record | Same requirement |
| Post-anesthesia note | Required before discharge | Required before discharge |
How Does CPT 00326 Affect Anesthesia Billing and Reimbursement?
Anesthesia billing uses a unique payment formula that differs from standard RVU-based physician fee schedule calculations. For CPT 00326, the payment formula is:
(Base Units + Time Units) × Geographic Conversion Factor = Reimbursement
| Component | CPT 00326 Value | Notes |
|---|---|---|
| Base units (CMS) | 7 | Reflects procedure complexity for this age/site |
| Time units | Variable (1 unit per 15 minutes) | Calculated from anesthesia start to end |
| Physical status units | 0–4 additional units | Varies by payer; many commercial plans include these |
| Qualifying circumstance units | See exclusion note below | +99100 should NOT be separately reported |
| Conversion factor | Locality-specific (CMS publishes annually) | 2026 conversion factors available at CMS Anesthesiologists Center |
Per the American Society of Anesthesiologists (ASA) Committee on Economics, when CPT 00326 is reported, the add-on code +99100 (Anesthesia for a patient of extreme age, younger than 1 year) should not also be reported. The reasoning: 00326 already inherently describes anesthesia for a patient younger than 1 year — the age complexity is embedded in the code selection itself. Reporting +99100 alongside 00326 constitutes duplicate billing and may trigger claim denials or post-payment audits.
This is a high-stakes distinction. Billing teams that apply +99100 routinely across all infant cases — without recognizing the 00326 exception — expose their practice to overpayment recoupment. Payers that process both codes without denying the add-on may later identify the pattern in audits.
What Modifiers Are Commonly Used With CPT 00326?
| Modifier | Description | When to Apply | Billing Impact |
|---|---|---|---|
| AA | Anesthesiologist performs personally | Anesthesiologist provides all care without directing a CRNA | Full anesthesia payment |
| QK | Medical direction by physician of 2–4 CRNAs | Anesthesiologist medically directs CRNAs in concurrent cases | 50% of allowable per case |
| QX | CRNA with medical direction | CRNA performing; anesthesiologist directing | CRNA bills 50%; physician bills 50% |
| QZ | CRNA without medical direction | Independent CRNA practice (where state law permits) | Full CRNA payment |
| AD | Supervision of >4 concurrent procedures | Medical supervision beyond 4 concurrent cases | Reduced to 3 base units per case |
| P1–P6 | ASA physical status classification | Required on every anesthesia claim | P3+ may increase payment under some commercial plans |
| QS | Monitored anesthesia care (MAC) | MAC appropriate for this procedure (rare in infants) | Payment varies by payer |
| 23 | Unusual anesthesia | Used when general anesthesia is required for a procedure normally done with local/regional | Justification required in documentation |
Are There Prior Authorization, Coverage Restrictions, or LCD Requirements?
- Medicare: Infants under 1 year are generally Medicaid beneficiaries, not Medicare. CPT 00326 is technically a covered Medicare code, but Medicare Advantage or dual-eligible claims are the more common scenario. Always verify beneficiary program enrollment.
- Medicaid: Coverage and payment rates vary by state. Importantly, most state Medicaid programs do not reimburse the add-on code +99100, making the 00326 exclusion rule even more significant for Medicaid billing.
- Commercial payers: Most cover 00326 for medically necessary infant laryngeal and tracheal procedures. Prior authorization is frequently required for elective or semi-elective procedures in infants; emergent cases typically bypass PA requirements.
- No national LCD specifically governs CPT 00326. Local Coverage Determinations for general anesthesia services from your regional Medicare Administrative Contractor (MAC) apply broadly.
- NCCI/CCI edits: Anesthesia codes are broadly subject to the bundling principle that only one anesthesia code is reported per operative session. See below for co-billing guidance.
What CPT or HCPCS Codes Are Commonly Billed Alongside CPT 00326?
When CPT 00326 appears on an anesthesia claim, the operative session will also include surgical CPT codes reported by the surgeon (on a separate claim) and potentially qualifying circumstance or physical status add-ons reported by the anesthesia provider. The surgical codes do not appear on the anesthesia claim itself.
| Associated Code | Description | Typical Pairing Context | Bundling Risk |
|---|---|---|---|
| 31515 | Laryngoscopy, direct, with or without tracheoscopy; for aspiration | Direct laryngoscopy for airway foreign body or secretions | No — separate surgeon claim |
| 31520 | Laryngoscopy, direct, diagnostic, with or without tracheoscopy; newborn | Newborn diagnostic laryngoscopy | No — separate surgeon claim |
| 31525 | Laryngoscopy, direct, with or without tracheoscopy; diagnostic, other than newborn | Diagnostic scope in infant >28 days | No — separate surgeon claim |
| 31600 | Tracheostomy, planned (separate procedure) | Infant requiring surgical airway | No — separate surgeon claim |
| +99100 | Anesthesia for patient of extreme age, <1 year | Qualifying circumstance add-on | YES — do not bill with 00326 |
| 99100 (standalone) | Same as above, sometimes billed in error as standalone | Billing error | YES — bundled/excluded |
Which Code Combinations Trigger NCCI or CCI Edits?
- CPT 00326 + CPT 00320: Mutually exclusive — never report both for the same encounter. One is age-appropriate; the other is not.
- CPT 00326 + any other primary anesthesia code (e.g., 00100, 00300): Per standard anesthesia NCCI policy, only the highest base unit anesthesia code is reported when multiple procedures occur under one anesthetic. Reporting two primary anesthesia codes is a significant edit trigger.
- CPT 00326 + +99100: Functionally excluded per ASA and payer policy; will result in denial or recoupment of the add-on when identified.
- Laryngoscopy (direct or endoscopic) for endotracheal tube placement is bundled into anesthesia services per the CMS NCCI Policy Manual, Chapter 2 and cannot be separately reported on the anesthesia claim.
What Coding Errors Should You Avoid With CPT 00326?
Anesthesia billing for this code carries a concentrated set of compliance risks due to the age restriction and the +99100 exclusion. The most frequently cited errors in order of audit exposure are:
- Billing +99100 alongside 00326. This is the highest-frequency error for this specific code. The age complexity is already captured in 00326 — the add-on is redundant and constitutes duplicate billing.
- Using 00320 instead of 00326 for an infant under 1 year. This is an undercoding error that results in one fewer base unit and likely triggers a denial if the patient’s age is verified on audit.
- Using 00326 for a patient who has already turned 1 year old. Age verification at the time of claim submission — not just at pre-auth — is required. If the patient turned 1 between authorization and surgery, the code must be updated.
- Reporting anesthesia time inaccurately. The anesthesia record must clearly document start and end times. Estimating or rounding time is an audit red flag; time units must be supported by contemporaneous documentation.
- Billing the surgical laryngoscopy or tracheoscopy code on the anesthesia claim. Procedural codes for the surgical intervention belong on the surgeon’s claim, not the anesthesia provider’s claim.
- Omitting the physical status modifier. Every anesthesia claim requires a P-status modifier. Claims submitted without it are incomplete and may deny outright or create downstream audit vulnerabilities.
- Failing to document the pre-anesthesia evaluation. Payers increasingly require a documented pre-anesthesia assessment as a condition of payment — especially for pediatric cases with high clinical complexity.
What Do Auditors and RAC Reviewers Look for When Reviewing CPT 00326 Claims?
- Date of birth discrepancy: Auditors routinely cross-reference the patient’s DOB on the claim against the date of service to verify the patient was under 12 months. A patient whose first birthday falls between pre-auth and the procedure date is a common audit flag.
- Improper pairing with +99100: Recovery Audit Contractors have targeted qualifying circumstance add-on codes broadly; this specific pairing is a well-documented overpayment pattern.
- Time documentation gaps: Missing start/stop times or suspicious time entries (e.g., identical times across multiple cases in a day) are audit red flags for anesthesia claims generally.
- Provider modifier mismatches: When a physician bills AA (personally performed) but OR scheduling records show concurrent cases, this can trigger medical direction reclassification and payment reduction.
- Multiple anesthesia codes for one operative session: Any claim with two primary anesthesia codes for the same patient on the same date is automatically flagged.
How Does CPT 00326 Relate to Other CPT Codes?
| Related Code | Relationship Type | Key Distinction |
|---|---|---|
| 00320 | Age-adjacent, mutually exclusive | Larynx/trachea and broader neck structures; age 1 year or older; 6 base units |
| 00322 | Mutually exclusive (different site/procedure) | Thyroid needle biopsy; 3 base units; not site-specific to larynx/trachea |
| 00300 | Broader anatomical umbrella | Head, neck, and posterior trunk integumentary procedures; not larynx/trachea specific |
| 00561 | Age-parallel (cardiac) | Anesthesia for cardiac surgery with pump in patients under 1 year; not applicable to larynx/trachea |
| 00834 | Age-parallel (hernia) | Anesthesia for hernia repair in patients under 1 year; site-exclusive |
| +99100 | Add-on code — excluded | Qualifying circumstance for extreme age; must NOT be reported with 00326 |
| +99116 | Add-on code — situational | Qualifying circumstance for utilization of controlled hypotension; may apply in complex infant cases if documented |
What Is the Correct Code Sequencing or Reporting Order When CPT 00326 Appears With Other Codes?
- Report CPT 00326 as the primary anesthesia code — listed first on the anesthesia claim.
- Append the appropriate provider modifier (AA, QK, QX, QZ, or AD) immediately after the base code.
- Append the physical status modifier (P1 through P6) as documented in the pre-anesthesia assessment.
- Add qualifying circumstance add-on codes if applicable — excluding +99100, which must not be reported. +99116 (controlled hypotension) or +99135 (induced hypothermia) may be appropriate if those techniques are employed and documented.
- Report only one primary anesthesia code per operative session, even if multiple laryngeal or tracheal procedures are performed sequentially. Use total case time for the single reported code.
Real-World Coding Scenario — How CPT 00326 Is Applied in Practice
A 4-month-old male presents to the pediatric ENT operating suite with progressive inspiratory stridor and a suspected subglottic hemangioma identified on prior flexible laryngoscopy. The pediatric ENT surgeon performs a direct microlaryngoscopy under general anesthesia to evaluate and laser-ablate the hemangioma. The anesthesiologist performs all anesthesia personally. Total anesthesia time is 45 minutes. The patient’s ASA physical status is documented as P2 (mild systemic disease).
Correct Code Application
- Anesthesia code: CPT 00326 — anesthesia for all procedures on the larynx and trachea in children younger than 1 year
- Provider modifier: AA — anesthesiologist personally performed
- Physical status modifier: P2
- Qualifying circumstances: None — +99100 is specifically excluded when 00326 is used
- Base units: 7
- Time units: 45 minutes ÷ 15 = 3 time units
- Total billable units: 7 + 3 = 10 units × locality-specific conversion factor
Common Mistake in This Scenario
- Incorrect: Reporting CPT 00326-AA-P2 + +99100
- Why it fails: The age complexity is already embedded in 00326’s descriptor. Adding +99100 constitutes duplicate reporting of the age qualifier. Per American Society of Anesthesiologists (ASA) guidance, this combination should not be reported. Payers that detect the pattern may deny the add-on and flag the practice for broader anesthesia billing review.
- Also incorrect: Using CPT 00320 because the surgeon’s operative report referenced the “neck” — the primary site was the larynx, which puts the anesthesia correctly under 00326 given the patient’s age.
Frequently Asked Questions About CPT Code 00326
What Is CPT Code 00326 Used For?
CPT 00326 is used to report anesthesia services provided for any procedure performed on the larynx or trachea in a patient who is younger than 1 year of age. It applies regardless of whether the procedure is diagnostic or surgical, as long as the anatomical site is the larynx or trachea and the patient is an infant.
Is CPT Code 00326 Still Valid in 2025 and 2026?
Yes, CPT 00326 remains an active, billable code with no changes to its descriptor for 2025 or 2026. Per the CMS Anesthesiologists Center, anesthesia base units are unchanged for CY 2025 and CY 2026, meaning CPT 00326 continues to carry 7 base units. Coders should verify annually against the AMA CPT Professional Edition for any descriptor revisions.
Can CPT 00326 and +99100 Be Billed Together?
No. CPT 00326 already describes anesthesia specifically for children younger than 1 year, so the age qualifier embedded in the code descriptor makes +99100 redundant. The American Society of Anesthesiologists explicitly advises that +99100 should not be reported alongside 00326. Billing both codes constitutes duplicate reporting and creates overpayment audit exposure.
How Many Base Units Does CPT 00326 Carry?
CPT 00326 carries 7 base units under the CMS nationwide anesthesia base unit schedule. This is one unit higher than CPT 00320 (6 base units), which covers the same anatomical site in patients aged 1 year or older — reflecting the recognized additional complexity of managing anesthesia for laryngeal and tracheal procedures in infants.
What Is the Difference Between CPT 00326 and CPT 00320?
CPT 00326 applies exclusively to patients younger than 1 year; CPT 00320 applies to patients aged 1 year or older. Additionally, 00320 covers a broader anatomical scope — including the esophagus, thyroid, larynx, trachea, and neck lymphatics — while 00326 is restricted to the larynx and trachea. CPT 00326 carries 7 base units versus 6 for CPT 00320.
What Modifier Should Be Used When a CRNA Performs Anesthesia for CPT 00326 Without Physician Direction?
When a CRNA independently administers anesthesia without physician medical direction, modifier QZ is appended to CPT 00326. If the CRNA is under medical direction of a physician, modifier QX is used on the CRNA’s claim, while the directing physician reports modifier QK (for 2–4 concurrent cases). State law and payer policy govern whether independent CRNA practice is recognized.
Does CPT 00326 Require Prior Authorization for Commercial Payers?
Prior authorization requirements vary by payer and by whether the procedure is elective or emergent. Many commercial payers require PA for planned laryngoscopy or tracheotomy in infants. Emergency airway cases typically bypass prior authorization requirements, but documentation of medical necessity should be comprehensive. Always verify PA requirements with the specific health plan before a scheduled pediatric airway procedure.
Key Takeaways for Billing and Coding CPT 00326
- CPT 00326 is an age-restricted anesthesia code — the patient must be younger than 1 year on the date of service; verify date of birth at every stage of the revenue cycle.
- The code carries 7 base units — one more than the related CPT 00320, which applies to the same anatomical area in older patients.
- Do not report +99100 alongside CPT 00326 — this is the most critical and most frequently misapplied rule for this specific code, and it is a documented anesthesia overpayment pattern.
- Total anesthesia payment is calculated as (7 base units + time units) × locality-specific conversion factor — time must be fully documented in the anesthesia record.
- The correct provider modifier (AA, QK, QX, QZ, or AD) and physical status modifier (P1–P6) are required on every claim; omitting either creates denial risk.
- Only one primary anesthesia code is reported per operative session, even if multiple laryngeal or tracheal procedures are performed; total anesthesia time covers all procedures performed.
- For in-depth anesthesia billing formula guidance, consult the CMS Medicare Claims Processing Manual, Chapter 12, Section 50, and review the CMS Anesthesiologists Center for annually updated conversion factors.
