Summary & Overview
HCPCS S3645: HIV-1 Antibody Testing of Oral Mucosal Transudate
HCPCS Level II code S3645 denotes an HIV-1 antibody test performed on oral mucosal transudate. This code identifies a non-blood, oral fluid diagnostic modality commonly used in outpatient and community screening environments for HIV surveillance and initial detection. Nationally, oral fluid testing plays a role in expanding access to screening, supporting public health outreach, and facilitating early identification of HIV infection.
Key payers examined include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find an overview of coding and clinical context, payer coverage considerations, and comparisons of common billing practices. The publication outlines typical sites of service and the clinical purpose of the test, and it highlights common modifiers used with HCPCS Level II reporting.
This summary provides practical context for billing and administrative staff, laboratory managers, and policy analysts seeking concise information on the code's clinical role, payer landscape, and what to expect in terms of documentation and claims processing. Data not available in the input is noted where applicable within detailed sections.
Billing Code Overview
HCPCS Level II code S3645 represents HIV-1 antibody testing of oral mucosal transudate. This service is a laboratory diagnostic test that detects antibodies to HIV-1 using oral fluid collected from the mucosal surfaces of the mouth. The test is typically performed in ambulatory outpatient settings, including community clinics, public health screening sites, and provider offices where point-of-care or sent-out oral fluid testing is offered.
Service type: Diagnostic laboratory test
Typical site of service: Outpatient/ambulatory setting (clinic, community screening site, provider office)
Clinical & Coding Specifications
Clinical Context
A 24-year-old sexually active individual presents to a community health clinic requesting HIV screening after a recent potential exposure. The clinic nurse performs a noninvasive oral mucosal transudate collection using a disposable oral swab kit. Specimen handling, point-of-care testing, or transport to a central laboratory occurs per clinic protocol. Results are documented in the electronic medical record; reactive results prompt confirmatory serum testing and linkage to care. Typical workflow: registration and consent, brief risk assessment and counseling, collection of oral mucosal transudate specimen, performance of the S3645 HIV-1 antibody test (either point-of-care or sent to lab), documentation of result, and follow-up counseling or confirmatory testing as indicated. Typical site of service is an outpatient clinic, community health center, mobile testing unit, or public health screening event.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
26 | Professional component | Use when reporting only the professional interpretation component if applicable to lab reporting arrangements. |
TC | Technical component |