Summary & Overview
CPT 80175: Lamotrigine Level Measurement
CPT code 80175 represents a laboratory assay to measure lamotrigine blood concentrations for therapeutic drug monitoring. Nationally, this test informs dosing decisions for patients on lamotrigine, a medication commonly used in seizure disorders and mood stabilization, helping clinicians balance efficacy and toxicity. Accurate measurement is important for individualized care, adherence assessment, and managing drug interactions.
Key payers covered in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find an overview of coding intent and clinical context, coverage considerations across major national payers, typical sites of service, common modifiers used with laboratory billing, and practical coding notes. The publication also summarizes typical use cases for ordering the assay, such as suspected toxicity, subtherapeutic response, or monitoring after dose changes.
This resource provides operational benchmarks and policy-relevant information useful to laboratory billing staff, clinicians ordering therapeutic drug monitoring, and revenue cycle professionals. Data not available in the input is noted where applicable, and the content focuses on national implications rather than state-specific rules.
Billing Code Overview
CPT code 80175 describes a laboratory test that measures the lamotrigine level in a patient's biological specimen. This test is a therapeutic drug monitoring assay used to assess serum or plasma concentrations of lamotrigine to inform clinical management.
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Service type: Clinical laboratory therapeutic drug monitoring
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Typical site of service: Clinical laboratory or hospital laboratory performing specialty chemistry testing
Clinical & Coding Specifications
Clinical Context
A typical scenario involves an outpatient or hospital-based therapeutic drug monitoring (TDM) encounter for a patient receiving lamotrigine for epilepsy or bipolar disorder. A neurologist, psychiatrist, or primary care provider orders a serum lamotrigine level to assess therapeutic concentration, suspected toxicity, subtherapeutic dosing, adherence, or drug interaction effects. The specimen (usually serum or plasma) is collected at the clinic, infusion center, emergency department, or hospital laboratory and sent to the clinical chemistry lab. The laboratory performs quantitative analysis and reports a numeric lamotrigine concentration to the ordering provider, who integrates the result with clinical status and concurrent medications to adjust dosing if indicated. Typical sites of service include outpatient hospital clinic, physician office, emergency department, and inpatient hospital laboratory processing for monitoring or urgent evaluation of possible toxicity.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
26 | Professional component | When billing for the physician or pathologist interpretation component if applicable separate from technical lab services |
90 | Reference (outside) laboratory |