Summary & Overview
HCPCS Level II S3630: Eosinophil Count, Blood, Direct
HCPCS Level II code S3630 represents a direct eosinophil count performed on peripheral blood. Eosinophil counts are clinically important for diagnosing and monitoring allergic conditions, parasitic infections, and certain hematologic disorders, making this laboratory measurement widely used across ambulatory and hospital settings. Nationally, standardized reporting and accurate coding for hematology tests support appropriate clinical decision-making and claims processing.
Key payers covered in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find an overview of coding context, common billing practices, and payer coverage considerations. The publication outlines clinical context for use of eosinophil counts, typical sites of service, and available benchmarking where provided. Where input data is incomplete, the document notes that additional payer-specific coverage rules and payment rates must be consulted directly with each insurer for definitive guidance.
This summary equips billing professionals, clinical laboratorians, and policy analysts with a concise reference to the purpose of S3630, the clinical scenarios in which a direct eosinophil count is ordered, and the types of payer policies and claims processes that commonly apply to hematology laboratory services.
Billing Code Overview
HCPCS Level II code S3630 describes Eosinophil count, blood, direct. This service is a hematology laboratory test that quantifies eosinophils directly in a peripheral blood specimen. The service type is diagnostic laboratory test, and the typical site of service is a clinical laboratory or hospital outpatient laboratory where blood counts and differential tests are performed.
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Clinical & Coding Specifications
Clinical Context
A 34-year-old outpatient presents to the hematology clinic with a 3-week history of progressive wheeze, episodic cough, and peripheral neuropathic symptoms. The clinician suspects eosinophilic-driven disease (for example, eosinophilic asthma or hypereosinophilic syndrome) and orders a peripheral blood eosinophil count to quantify circulating eosinophils. A venous blood sample is collected in the laboratory phlebotomy area or clinic draw station, sent to the hospital core laboratory or a reference lab, and processed on an automated hematology analyzer or by direct microscopic count if requested. Results are returned to the ordering provider and used to guide diagnosis, evaluate disease severity, monitor response to corticosteroid or biologic therapy (such as anti–IL-5 agents), and determine need for further testing (bone marrow biopsy, allergy testing, or infectious workup). Typical site of service is outpatient laboratory, clinic-based phlebotomy, or hospital laboratory. Service type: diagnostic laboratory test (hematology).
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
26 | Professional component | Use when only the professional interpretation/component of a test (interpretation by pathologist or laboratory physician) is billed separately. |
TC |