CPT code 00450: Anesthesia for clavicle and scapula procedures

Key Takeaways

CPT code 00450 describes anesthesia for surgical procedures on the clavicle and scapula not otherwise specified, including fracture repairs, AC joint reconstructions, and hardware removal

Base unit value is 5; reimbursement is calculated as (Base Units + Time Units) x Conversion Factor per CMS guidelines

Six modifiers apply: AA, QZ, QK, AD, QX, and QY, each reflecting a different provider type or supervision arrangement

Pabau’s claims management software helps billing teams track, submit, and reconcile anesthesia claims to reduce denials

CPT code 00450 is the anesthesia code for procedures on the clavicle and scapula not otherwise specified, covering fracture repairs, AC joint reconstructions, scapula fixation, and hardware removal. It carries 5 base units and sits within the 00400-00474 range of shoulder-girdle anesthesia codes. This reference covers the code’s definition, base unit value, reimbursement formula, Medicare fee schedule rates, modifiers, documentation requirements, ICD-10 pairings, and the most common billing mistakes.

Whether you are an anesthesiologist, a Certified Registered Nurse Anesthetist (CRNA), or a billing specialist, getting CPT code 00450 right the first time means fewer payer rejections and a cleaner revenue cycle.

CPT code 00450: Definition and clinical description

CPT code 00450 is the American Medical Association (AMA) procedure code for anesthesia services provided during surgical procedures on the clavicle and scapula that are not otherwise specified. It sits within the 00400-00474 range of anesthesia codes covering integumentary and musculoskeletal procedures of the shoulder girdle.

The code applies whenever anesthesia is administered for a procedure specifically targeting the clavicle or scapula that doesn’t have its own dedicated code, regardless of whether the anesthesia technique is general, regional, or monitored anesthesia care (MAC). Patient positioning, surgical complexity, or comorbidities do not change the code; the anatomical procedure site determines selection, typically confirmed through imaging and physical exam findings such as a trapezius tear test.

Clinical procedures covered

CPT code 00450 applies to anesthesia for a range of surgical interventions on the clavicle and scapula, many of which start as acute injuries treated in sports medicine practices. Correctly identifying the procedure site before coding prevents the most common selection error: using a related shoulder code when the surgery specifically involves one of these two bones.

Common procedures where CPT code 00450 is the appropriate anesthesia code include:

• Open reduction and internal fixation (ORIF) of clavicle fractures
• Clavicle excision or resection (including distal clavicle resection for AC joint arthritis)
• Acromioclavicular (AC) joint reconstruction or stabilization
• Scapula fracture repair or open fixation
• Scapulothoracic fusion or arthrodesis
• Removal of hardware previously placed in the clavicle or scapula

Procedures on the glenohumeral joint (shoulder joint proper), the rotator cuff, or the proximal humerus fall outside this code’s scope. Those cases belong to different anesthesia codes, covered in the related codes section below. Accurate procedure-site documentation in the operative note is the foundation for correct code selection, and it carries into recovery too, since physical therapy practices rely on the same operative details to build a rehabilitation plan.

CPT code 00450 base units and the reimbursement formula

CPT code 00450 carries a base unit value of 5, as established by the AMA’s Relative Value Guide for Anesthesiology. Base units reflect the inherent complexity and risk of anesthetizing a patient for a given procedure site, independent of time.

Medicare and most commercial payers calculate anesthesia reimbursement using a standard formula. Understanding how time units feed into that formula is critical for accurate billing.

Worked example: A 60-minute clavicle ORIF generates 4 time units (60 min / 15 = 4). Adding the 5 base units gives 9 total units. At a hypothetical conversion factor of $21.00, the claim value is $189.00. Actual conversion factors vary by Medicare locality and are updated annually by the CMS Physician Fee Schedule. Always verify the current rate for your MAC jurisdiction before finalizing claims.

Medicare fee schedule and payer rates for CPT code 00450

Medicare reimbursement for CPT code 00450 is governed by the annual Physician Fee Schedule published by the Centers for Medicare and Medicaid Services (CMS). Rates are not uniform nationally; they reflect geographic practice cost adjustments applied through Medicare Administrative Contractor (MAC) locality multipliers.

Private payer rates differ significantly from Medicare and are set through individual payer contracts. Some payers follow the Medicare structure (base units x conversion factor x time), while others use a flat-rate or percentage-of-billed-charges approach. Verify your contract terms for each payer. Use the FastRVU 2026 RVU lookup to check current relative value unit data for anesthesia codes.

Modifiers for CPT code 00450

Modifier selection is the highest-stakes element of billing CPT code 00450. The wrong modifier changes the reimbursement percentage, can trigger a payer audit, and in some cases results in complete claim rejection. Six modifiers apply to this code, each reflecting a distinct provider-type and supervision arrangement.

CRNA billing under CPT code 00450

CRNA modifier selection depends on two factors: whether the state has opted out of the Medicare physician supervision requirement, and whether a physician anesthesiologist is directing the case. In opt-out states, CRNAs bill with QZ and receive 100% of the allowed amount. In non-opt-out states, CRNAs working under physician direction bill with QX, while the directing physician bills the same procedure with QK. Both claims pay at 50%, totaling 100% of the allowed amount when split correctly.

Supervision opt-out status is state-specific and subject to change. Verify your state’s current Medicare opt-out status before applying QZ. Misapplying QZ in a non-opt-out state without an opt-out declaration on file is a compliance risk under healthcare billing compliance frameworks and OIG audit guidelines. For practices managing CRNA credentialing and billing records, digital forms can standardize how supervision arrangements are documented at the point of care.

Documentation requirements for CPT code 00450

Missing or incomplete documentation is the leading cause of post-payment audits for anesthesia claims. CMS requires a complete anesthesia record for every billable case. Four core documents must be present in the patient record to support a 00450 claim.

• Pre-anesthesia evaluation: Completed before the procedure begins. Must document ASA physical status classification, relevant medical history, airway assessment, and the plan for anesthesia. This establishes medical necessity and justifies the anesthesia approach.
• Intraoperative anesthesia record: Continuous time-stamped record of anesthesia start and stop times, vital signs, agents administered, and any intraoperative events. Start and stop times directly support time unit calculation on the claim.
• Post-anesthesia care note: Documents patient status on transfer from the operating room to PACU, including responsiveness, vital signs, and any immediate post-procedural concerns.
• Medical necessity documentation: For MAC cases, the record must include specific documentation of why MAC was medically necessary rather than a lesser level of monitoring. CMS Local Coverage Determinations govern covered diagnoses for MAC under codes in the 00400-00474 range.

Practices that route anesthesia documentation through structured medical forms at their healthcare practice reduce the likelihood of missing fields at audit. Consistent use of HIPAA-compliant paperless workflows also creates an auditable digital trail for every claim. The AAPC Codify CPT lookup provides additional coding guidance and payer policy references for anesthesia documentation standards.

ICD-10 codes used with CPT code 00450

Every anesthesia claim requires a supporting ICD-10-CM diagnosis code to establish medical necessity. The diagnosis code must accurately reflect the condition requiring surgery on the clavicle or scapula. The table below lists common ICD-10 pairings; the appropriate code depends on the patient’s specific diagnosis, not simply the surgical site. Treat these as illustrative examples, since payer coverage criteria vary.

ICD-10 code selection should always reflect the documented diagnosis, not the procedure performed. The same coding discipline applies to other anesthesia codes, including 01920, where diagnosis-procedure linkage is just as critical for clean claims. For the current official code descriptions, refer to the CDC/NCHS ICD-10-CM web tool.

Related CPT codes: 00454 and 00474

CPT code 00450 sits near two codes that are easy to confuse it with on a claim. Both cover different procedures despite the numeric proximity, and mixing them up creates audit exposure. The table below distinguishes them.

00454 is reserved for a clavicle biopsy alone, a diagnostic procedure with a lower base unit value than the surgical repairs covered by 00450. 00474 covers radical rib resection and has no direct relationship to clavicle, scapula, or shoulder anesthesia despite sitting in the same code block. Billing 00454 for a clavicle ORIF is undercoding, and billing 00450 for a diagnostic biopsy is upcoding. Confirm the procedure documented in the operative note before selecting between these codes. For broader CPT coding context, see how CPT code selection is managed across different specialty billing scenarios.

Common billing errors and how to avoid them

Three billing errors account for the majority of denied or audited CPT code 00450 claims. The same documentation gaps that undermine medical decision making claims show up here too, and each is preventable with the right workflow controls.

• Wrong modifier based on supervision status: Using modifier AA when the anesthesiologist was medically directing a CRNA (requires QK + QX split billing) is the most frequent modifier error. Review supervision arrangements before the claim leaves the billing queue.
• Missing or imprecise time documentation: Time units are calculated from the anesthesia record’s start and stop times. Vague entries like “approximately 60 minutes” do not satisfy Medicare documentation standards. The record must show the exact clock time anesthesia induction began and the exact time the provider’s presence ended.
• Procedure-site mismatch between the operative note and the claim: The CPT code on the claim must match the anatomical site documented in the operative note. If the operative report describes a glenohumeral joint repair but 00450 is billed, payers will deny or request additional records. Coders should read the operative note, not the surgical booking description, when assigning the anesthesia code.

Additional errors include failing to append an ICD-10 code that supports medical necessity, billing MAC without documentation of why MAC was specifically required, and omitting the post-anesthesia care note from the chart. Practices managing multi-provider anesthesia teams benefit from reviewing the billing workflow patterns used across multi-specialty CPT documentation and checking EHR integration options that connect anesthesia records directly to the billing module.

How claims management software reduces errors for CPT code 00450

Manual anesthesia billing creates gaps at exactly the points where CPT code 00450 claims fail most often: modifier assignment, documentation completeness, and claim submission accuracy. Purpose-built claims management software helps close some of these gaps before a claim reaches the payer.

Pabau’s claims management software helps billing teams submit, track, and reconcile insurance claims in one place, rather than juggling separate spreadsheets or payer portals. Practices can see where a claim sits in the process and catch missing information before it turns into a denial, then reconcile payments once they come back from the payer. Learn more about how medical office HIPAA compliance applies to anesthesia documentation workflows and electronic records.

Simplify anesthesia claims with Pabau

Pabau’s claims management tools help your billing team track claim status, catch missing information before submission, and reconcile payments so CPT code 00450 claims move through the payer process with fewer delays.

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Conclusion

CPT code 00450 is a straightforward code with a narrow failure window: 5 base units, six possible modifiers, and strict documentation requirements that directly determine whether a claim pays or gets denied. The most preventable errors are modifier mismatches driven by supervision status and time documentation that does not meet Medicare’s specificity standards.

Practices that build documentation and modifier-selection checks into their billing workflow catch these errors before submission rather than after denial. Pabau’s claims management software supports that workflow by helping your billing team track, submit, and reconcile claims accurately. To see how it works in practice, book a demo with the Pabau team.

Continue your research

Need to understand how CPT codes are structured across specialties? Coaching CPT codes walks through CPT selection principles and billing workflows applicable across multiple specialty types.

Managing multi-specialty billing across your practice? EHR integration for medical practices covers how connected billing and records systems reduce claim errors and manual rework.

Need a structured documentation framework for surgical procedures? Medical forms at your healthcare practice explains how structured digital forms support audit-ready anesthesia records.

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