Summary & Overview
CPT 0079U: ToxLok™ Urine Specimen Identity Verification
CPT code 0079U designates ToxLok™, a Proprietary Laboratory Analyses (PLA) test by InSource Diagnostics that confirms urine specimen identity through DNA comparison of a buccal swab and a urine sample collected simultaneously. The code captures a single, manufacturer-specific molecular diagnostic service used to reduce sample mix-ups in urine-based testing programs, such as substance use monitoring and forensic or clinical toxicology workflows. Nationally, this code matters as labs and payers navigate coverage and billing for increasingly specific proprietary assays that support sample integrity and chain-of-custody processes.
Key payers reviewed include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise explanation of the clinical context for specimen verification, the service setting implications for laboratories and collection sites, and what typical payer consideration looks like for PLA-designated tests. The publication outlines expected benchmarking topics and policy updates that affect proprietary molecular diagnostics, and provides guidance on where to look for payer policy language and coverage criteria. Data not available in the input is noted where applicable.
Billing Code Overview
CPT code 0079U is a Proprietary Laboratory Analyses (PLA) code that describes a single, manufacturer-specific laboratory test: ToxLok™ by InSource Diagnostics. The test verifies that a urine specimen is from the intended person by comparing DNA from a concurrently collected buccal (cheek) swab and the urine specimen.
Service type: Specimen identity verification using molecular/DNA comparison
Typical site of service: Clinical laboratory or point-of-collection testing linked to urine drug testing programs
Clinical & Coding Specifications
Clinical Context
A typical patient scenario involves a patient presenting for urine drug testing, forensic collection, or specimen validity testing where chain-of-custody and specimen identity must be confirmed. At intake, a trained collector obtains a buccal (cheek) swab and a contemporaneous urine specimen from the same patient. Both specimens are labeled, documented, and sent to the laboratory. ToxLok™ (0079U) is performed by the manufacturer or designated lab to compare DNA from the buccal swab and extracted DNA from the urine specimen to confirm the urine originates from the intended individual. Results are reported as a match, non-match, or inconclusive, and are used to validate test results for clinical care, legal proceedings, workplace testing, or medication monitoring. Typical sites of service include outpatient clinics, addiction medicine programs, occupational health facilities, forensic collection centers, and commercial laboratories handling mailed or couriered specimens.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
22 | Increased procedural services | Use if laboratory documents and bills with an unusual and significant incremental cost or complexity beyond typical testing for the assay (rare for PLA codes). |
26 |