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 | Professional component | Use when billing only the professional component of a split service, if applicable for reporting lab director professional interpretation separate from technical lab work. |
52 | Reduced services | Use if testing performed at less than full service as documented (e.g., limited analysis). |
53 | Discontinued procedure | Use if testing was started but discontinued prior to completion for documented clinical reasons. |
55 | Postoperative management only | Generally not applicable but included if billing relates to postoperative specimen verification in a bundled episode. |
AD | Laboratory supervision by a different individual | Use when an alternative laboratory director or supervising clinician provided oversight as permitted by payer rules. |
QK | Medical direction of two-3 qualified individuals | Use when the lab director medically directs multiple qualified personnel performing the test under CMS laboratory direction rules. |
QX | Modifier to indicate services performed by a non-physician practitioner | Use when applicable for supervision or performer identification per payer rules. |
QY | Medical direction of one qualified individual | Use when the lab director medically directs a single qualified individual performing the test. |
TC | Technical component | Use when billing only the technical component of the test (laboratory processing and analysis) without the professional interpretation. |
| Taxonomy Code | Specialty | Notes |
|---|---|---|
| 207Q00000X | Clinical Laboratory | Common specialty performing laboratory testing and specimen verification. |
| 207K00000X | Toxicology | Specialty focused on drug testing and specimen validity services. |
| 208D00000X | Pathology | Lab directors or pathologists may oversee or interpret DNA comparisons and forensic validation. |
| 3336S0110X | Addiction Medicine | Clinicians in addiction programs commonly order specimen identity testing to validate urine results. |
| 364SF0200X | Occupational Medicine | Occupational health services order specimen verification for workplace drug testing and forensics. |
Related Diagnoses
| ICD-10 Code | Description | Clinical Relevance |
|---|---|---|
R78.0 | Abnormal drug test results | Used when a urine drug screen yields unexpected or disputed results and specimen identity verification is required. |
Z13.89 | Encounter for screening for other disorder | Use when screening workflows include specimen verification for regulatory or surveillance purposes. |
Z71.51 | Drug abuse counseling and surveillance of drug therapy | Applicable for monitoring compliance where specimen identity confirmation supports treatment decisions. |
Z03.89 | Encounter for observation for other suspected diseases and conditions | Used in settings where verification of specimen identity is needed pending clinical or forensic determination. |
R79.9 | Abnormal findings in laboratory tests, unspecified | Broad code used when lab abnormalities prompt confirmatory identity testing of the specimen. |
Related CPT Codes
| CPT Code | Description | Relationship to This Procedure |
|---|---|---|
0080U | Genomic test for specimen identity verification (example PLA companion code) | May be performed alongside 0079U when additional proprietary specimen identity assays or alternative vendor tests are used in the same workflow. |
G0480 | Drug test, definitive, multiple drug classes, each procedure | Frequently ordered in the same episode of care; 0079U confirms specimen identity when definitive drug testing is reported. |
80305 | Drug screen, presumptive, any number of drug classes by instrumented chemistry analyzers | Often preceded by presumptive screening; if confirmation testing is discrepant or chain-of-custody questioned, 0079U may be ordered. |
87635 | Infectious agent detection by nucleic acid (example NAAT) | Not directly related clinically but represents lab-based nucleic acid testing workflows; included as an analogous lab molecular procedure performed in the same laboratory setting. |
89049 | Urinalysis, by automated instrument with microscopy | May be ordered in the same visit to assess urine characteristics when specimen validity or contamination is a concern; 0079U provides identity verification complementary to urinalysis. |