Summary & Overview
HCPCS Level II C9164: Cantharidin 0.7% Topical Single-Unit Applicator
HCPCS Level II code C9164 describes a single-unit topical applicator containing cantharidin 0.7% (3.2 mg) used for localized cutaneous treatment. As a HCPCS Level II supply/drug code, it identifies the product for billing when providers administer or dispense this topical pharmacologic agent in ambulatory settings. Nationally, accurate coding of this product matters for claims processing, inventory tracking, and consistent clinical documentation of topical therapies.
Key payers in the analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of the code’s clinical context, typical sites of service, and common billing modifiers used with HCPCS Level II supply codes. The publication outlines where this code fits in service lines that manage dermatologic topical treatments and highlights typical administrative considerations relevant to payers and provider billing teams.
This summary provides benchmarks for how the code is categorized, practical clinical context for its use, and references to payer coverage considerations where available. Data not available in the input is noted explicitly in relevant sections.
Billing Code Overview
HCPCS Level II code C9164 represents cantharidin for topical administration, 0.7%, single unit dose applicator (3.2 mg). This product is a topical pharmacologic agent supplied in a single-unit applicator designed for direct cutaneous application.
Service type: Topical pharmacologic treatment
Typical site of service: Outpatient clinics, dermatology offices, and other ambulatory care settings where topical treatments are administered
Clinical & Coding Specifications
Clinical Context
A typical patient is an adult seen in a dermatology clinic for treatment of localized molluscum contagiosum or small superficial viral warts refractory to first-line therapies. The clinician prepares a single-use topical applicator containing cantharidin 0.7% (C9164) to apply a controlled blistering agent to one or a few lesions. The workflow: evaluation and consent; lesion cleansing and isolation; application of the C9164 single unit dose applicator to affected lesions for a prescribed contact period; removal or neutralization per protocol; post-application instructions and dressing if needed; brief observation for immediate adverse reaction. Documentation includes indication, informed consent, lesion count and locations, applicator lot number, contact time and removal method, any local anesthetic or adjunctive measures, patient instructions, and follow-up plan. Typical sites of service are outpatient dermatology clinics, ambulatory surgical centers for multiple lesion treatments, and physician offices. Patient scenario modifiers may include medical complexity or bilateral/multiple sites when applicable.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
22 | Increased procedural services | Use when work required is substantially greater than typical for topical application (extensive multiple-site treatment documented). |