Summary & Overview
CPT 87220: KOH Microscopic Fungal Examination
CPT code 87220 represents a microscopic fungal examination using potassium hydroxide (KOH) to detect fungal elements in specimens such as nail clippings, skin scrapings, or hair shafts. This relatively simple, low-cost laboratory procedure plays a key role in diagnosing dermatophyte and other superficial fungal infections and often guides antifungal treatment decisions. It is widely used across outpatient clinics, dermatology practices, and clinical laboratories, making it an important procedure in ambulatory and laboratory service utilization.
Key payers covered in this analysis include Aetna, Blue Cross Blue Shield, Cigna, UnitedHealthcare, and Medicare. Readers will find a concise overview of the clinical purpose of CPT code 87220, the typical sites where the service is performed, and the common contexts in which clinicians order a KOH preparation. The publication also outlines benchmarking topics and policy considerations relevant to laboratory billing and coverage, including typical use cases and how the test fits into diagnostic workflows. Data not available in the input will be noted where applicable.
Billing Code Overview
CPT code 87220 describes a laboratory micologic examination in which a lab analyst or microbiologist adds potassium hydroxide (KOH) as a clearing agent and examines a specimen for fungal elements. The procedure is typically performed on nail clippings, skin scrapings, or hair shaft specimens to detect dermatophytes and other fungal forms.
Service Type: Microscopic fungal examination (KOH preparation)
Typical Site of Service: Clinical laboratory, hospital laboratory, or outpatient clinic specimen-processing area
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Clinical & Coding Specifications
Clinical Context
A 45-year-old patient presents to a dermatology clinic with brittle, discolored toenails and a pruritic, scaly patch on the plantar surface of the foot. The clinician performs a focused history and physical exam and collects nail clippings and superficial skin scrapings at the visit. The specimen is sent to the clinic laboratory or an outpatient pathology/microbiology lab. A lab analyst or microbiologist prepares the sample by adding potassium hydroxide (KOH) as a clearing agent and examines the specimen microscopically for fungal elements such as hyphae or spores. Results are documented in the laboratory report and communicated to the ordering clinician for correlation with clinical findings and treatment planning. Typical site of service: outpatient dermatology clinic or outpatient laboratory. Service type: diagnostic mycological microscopy using KOH preparation (87220).
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
25 | Significant, separately identifiable evaluation and management service by the same physician on the same day of the procedure | Use when the clinician performs an E/M visit that is distinct from specimen collection for 87220. |