Summary & Overview
CPT 80199: Tiagabine Level Measurement
CPT code 80199 denotes a laboratory assay to determine tiagabine drug levels in a patient specimen, a form of therapeutic drug monitoring with clinical importance for dosing, safety, and efficacy of tiagabine therapy. Nationally, such assays support individualized medication management for patients treated with tiagabine, particularly when clinical response is unclear, drug interactions are possible, or adverse effects are suspected. Payers of interest in coverage and reimbursement discussions include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare.
This publication provides a concise overview of CPT code 80199, covering clinical context, where the test is typically performed, and the implications for lab and clinical workflows. Readers will find benchmarks for typical sites of service and payer considerations where available, a summary of common modifiers associated with laboratory services, and guidance on where to locate related coding resources. Data not available in the input will be noted as such. The material is intended for billing managers, laboratory directors, and policy analysts looking for a national-level summary of the code's purpose and operational context.
Billing Code Overview
CPT code 80199 describes a laboratory test that measures the level of tiagabine in a patient's biological specimen. This service is a therapeutic drug monitoring assay used to quantify tiagabine concentrations to inform medication management.
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Service type: Clinical laboratory testing (therapeutic drug level measurement)
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Typical site of service: Hospital laboratory, independent reference laboratory, or outpatient clinic laboratory
Clinical & Coding Specifications
Clinical Context
A patient receiving tiagabine (an anticonvulsant) presents for therapeutic drug monitoring after a recent dose adjustment for seizure control or because of suspected toxicity. A blood specimen is collected in an outpatient phlebotomy area, emergency department, or inpatient ward and sent to a clinical laboratory. The laboratory performs a quantitative assay to determine the serum or plasma level of tiagabine to assess adherence, guide dosing, or investigate adverse effects such as increased sedation, dizziness, or signs of toxicity. Results are reported to the ordering neurologist, epileptologist, or primary care provider for clinical interpretation and medication management. Typical sites of service include hospital laboratories, independent clinical laboratories, outpatient clinics with laboratory draw stations, and emergency departments.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
00 | Default/No modifier | Use when no other modifier is applicable for the service. |
11 | Primary service | Use when this lab test is the primary procedure on the claim. |