Summary & Overview
CPT 80335: Assay for Tricyclic and Cyclical Antidepressants
CPT code 80335 identifies a laboratory assay that detects or measures one or two tricyclic and other cyclical antidepressants in a patient specimen. This test is relevant nationally for psychiatric care, toxicology, and therapeutic drug monitoring, supporting clinical decisions about antidepressant dosing, adherence, and potential toxicity. As a focused toxicology panel, it affects laboratory workflows, coding compliance, and payer coverage determinations across inpatient and outpatient settings.
Key payers in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find an explanation of the clinical context for ordering 80335, typical sites of service, and the kinds of clinical questions the assay addresses. The publication provides benchmarks for utilization and billing practices where available, common modifier usage, and intersections with policy updates that influence coverage and documentation requirements.
The content aims to clarify coding intent and clinical utility so billing, laboratory, and clinical teams can align documentation with payer expectations. Data not available in the input will be noted where applicable.
Billing Code Overview
CPT code 80335 describes a laboratory test in which the lab analyst measures the amount of, or detects the presence of, one or two tricyclic and other cyclical antidepressants in a patient specimen. This service is a toxicology/drug assay focused on psychiatric medications used to monitor therapy, assess compliance, or evaluate potential toxicity.
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Service type: Clinical laboratory test — qualitative and/or quantitative drug assay for tricyclic and cyclical antidepressants
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Typical site of service: Hospital or independent clinical laboratory, outpatient phlebotomy/ambulatory collection sites, or other certified laboratory settings
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Clinical & Coding Specifications
Clinical Context
A 42-year-old patient treated for major depressive disorder presents to an outpatient laboratory after their psychiatrist requests drug monitoring to assess adherence and therapeutic drug levels of tricyclic and other cyclical antidepressants. A blood specimen is collected in the ambulatory phlebotomy area. The laboratory receives the specimen, performs an immunoassay or chromatographic testing per protocol to detect and quantify one or two tricyclic and related cyclical antidepressants, documents results in the electronic medical record, and reports findings to the ordering clinician for medication management and safety monitoring. Typical sites of service include outpatient hospital laboratories, independent clinical laboratories, and hospital inpatient labs when monitoring is ordered during admission. The clinical workflow includes order entry, specimen collection, specimen accessioning, analytical testing, quality control, result verification by a laboratory professional, and transmission of results to the treating psychiatrist or primary care provider.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
26 | Professional component | Use when billing only the professional interpretation/reading component provided by a physician or qualified person for the test. |
TC |