Summary & Overview
HCPCS G9364: Sinusitis Caused by Bacterial Infection
HCPCS Level II code G9364 designates encounters for sinusitis caused by, or presumed to be caused by, bacterial infection. As a diagnosis-driven HCPCS Level II code, it is used to identify patient encounters where bacterial etiology guides clinical management and potential procedural or therapeutic decisions. Nationally, clear coding for bacterial sinusitis affects claims processing, utilization tracking, and antimicrobial stewardship monitoring across payers.
Key payers covered in this overview include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise orientation to what G9364 represents clinically and operationally, how it maps to typical sites of service, and which major payers commonly adjudicate claims for this condition. The publication also outlines expected benchmarks and operational considerations, such as encounter settings, coding accuracy implications, and areas where policy updates or payer-specific requirements may affect claims.
This summary is intended for national audiences including coding specialists, billers, clinicians, and policy analysts seeking a clear, practical reference for HCPCS Level II code G9364 and its role in classifying bacterial sinusitis encounters.
Billing Code Overview
HCPCS Level II code G9364 denotes sinusitis caused by, or presumed to be caused by, bacterial infection. This code represents evaluation and management or encounter-level reporting tied to a clinical diagnosis of bacterial sinusitis rather than viral or allergic causes.
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Service type: Diagnostic evaluation and treatment management for bacterial sinusitis
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Typical site of service: Ambulatory clinic, urgent care, emergency department, or other outpatient settings where patients present with acute sinusitis symptoms
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Clinical & Coding Specifications
Clinical Context
A 38-year-old adult presents to an outpatient otolaryngology clinic with a 10-day history of purulent nasal drainage, facial pressure localized to the maxillary and ethmoid regions, nasal congestion, and low-grade fever. The clinician documents focal tenderness over the maxillary sinuses, purulent nasal secretions on anterior rhinoscopy, and elevated inflammatory markers. Symptoms began after an upper respiratory infection and have progressed despite symptomatic care. The working diagnosis is acute bacterial rhinosinusitis. The workflow includes history and focused physical exam, point-of-care nasal endoscopy if available, possible sinus imaging (plain radiograph or CT if complications or atypical course), microbiology testing only if failure of first-line therapy or severe infection, and initiation of guideline-directed antibiotic therapy and adjunctive symptomatic measures. If procedural intervention is required (e.g., bedside drainage of a sinus abscess or endoscopic sinus surgery for complicated or refractory disease), operative documentation, informed consent, perioperative anesthesia coding, and appropriate modifier usage for unusual circumstances are recorded.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
22 | Increased procedural services | Use when work required is substantially greater than typical for the service, documented with justification. |