Summary & Overview
CPT 80188: Primidone Quantitative Assay
CPT code 80188 identifies a laboratory technical procedure that quantifies primidone levels in a patient specimen. As a therapeutic drug monitoring assay, this code supports clinical decisions about anticonvulsant dosing, adherence, and toxicity management. Nationally, accurate reporting of such drug-level assays affects clinical care pathways, laboratory workflow, and payer coverage practices.
Key payers covered in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find an overview of the clinical context for primidone testing, typical sites of service, and what this code represents in laboratory billing. The publication also outlines common modifiers and payment considerations associated with laboratory services where applicable, and summarizes typical use cases for therapeutic drug monitoring.
The content is intended to help billing professionals, laboratory directors, and policy analysts understand the role of CPT code 80188 within lab service lines, including operational implications for clinical laboratories and hospital labs. Data not available in the input will be noted where relevant.
Billing Code Overview
CPT code 80188 describes a laboratory technical service to quantitate the amount of primidone, an anticonvulsant medication, in a patient specimen. The service involves analytical measurement performed by a laboratory analyst to determine serum or plasma concentration of primidone for therapeutic drug monitoring or toxicity assessment.
Service Type: Therapeutic drug monitoring / quantitative laboratory assay
Typical Site of Service: Clinical laboratory or hospital laboratory (specimen-based testing)
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Clinical & Coding Specifications
Clinical Context
A typical patient is an adult or pediatric patient receiving antiepileptic therapy with primidone for seizure disorder or essential tremor who requires therapeutic drug monitoring. The clinician (neurologist, primary care physician, or movement disorders specialist) orders a serum primidone level when there is concern for subtherapeutic dosing, suspected toxicity, altered mental status, breakthrough seizures, signs of drug adverse effects (sedation, ataxia), potential drug interactions, or to establish baseline steady-state concentration after a dose change. Specimen collection is performed in an outpatient phlebotomy clinic, hospital inpatient unit, emergency department, or ambulatory infusion center. The specimen (serum or plasma) is sent to a clinical laboratory where a laboratory analyst performs the technical assay to quantitate primidone using methods such as high-performance liquid chromatography (HPLC) or mass spectrometry. The laboratory provides a numeric concentration with reference range and a technical report; a pathologist or clinical chemist may provide an interpretive comment if required. Results are routed to the ordering provider’s electronic health record and used to guide medication dose adjustments, additional testing, or clinical management.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
00 | No modifier — default reporting | Use when no special circumstance applies to the lab test. |