HCPCS Level II code G0481 denotes a definitive drug test using high-specificity analytical methods (for example, GC/MS and LC/MS) that can identify individual drugs and distinguish structural isomers, with required internal standards and calibration controls. It covers qualitative or quantitative testing, includes specimen validity assessment, and is billed per day for testing 8–14 drug classes. This code matters nationally because definitive toxicology testing underpins clinical decision-making, forensic and workplace testing, and payer coverage determinations for high-complexity laboratory services.

Key payers addressed include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise explanation of the clinical and laboratory context for G0481, typical sites of service, and how the test is characterized. The publication also outlines expected content in benchmarking and policy sections: utilization benchmarks, billing and coding guidance, common modifier considerations, and payer coverage patterns where available. Policy updates and payer-specific requirements that affect coverage and billing workflows are summarized, and implications for laboratory operations and clinical ordering practices are provided. Data not provided in the input (for example, payer-specific rates or ICD-10 mappings) are noted as unavailable where relevant.