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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.

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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.

Service type: Clinical laboratory test — qualitative and/or quantitative drug assay for tricyclic and cyclical antidepressants
Typical site of service: Hospital or independent clinical laboratory, outpatient phlebotomy/ambulatory collection sites, or other certified laboratory settings

Data not available in the input.

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CPT 80335: Assay for Tricyclic and Cyclical Antidepressants

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Billing Code Overview

Service type: Clinical laboratory test — qualitative and/or quantitative drug assay for tricyclic and cyclical antidepressants
Typical site of service: Hospital or independent clinical laboratory, outpatient phlebotomy/ambulatory collection sites, or other certified laboratory settings

Data not available in the input.

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`	Technical component	Use when billing only the technical component (laboratory equipment, supplies, and technician work) for the test.
`90`	Reference (outside) laboratory	Use when test performed by an outside reference laboratory and the submitting provider bills for the service.
`91`	Repeat clinical diagnostic laboratory test	Use when the same test is repeated on the same day to obtain subsequent test results.
`52`	Reduced services	Use if the laboratory performs a reduced service relative to the full test procedure.
`53`	Discontinued procedure	Use when the test process was started but discontinued for clinical reasons.
`59`	Unbundling distinct procedural service	Not in the provided list; excluded.
`90` (duplicate)	See above	See above
`91` (duplicate)	See above	See above
`QX`	Modifier for certified nurse-midwife	Use only when applicable to non-physician practitioner billing relationships (rare for lab billing).
`QY`	CRNA service with medical direction	Use only when applicable to anesthesia supervision (generally not applicable).
`AS`	Physician assistant services	Use when a physician assistant furnishes services that are payable under the PA taxonomy and billing rules.

Taxonomy Code	Specialty	Notes
208D00000X	Pathology & Laboratory Medicine	Laboratories and pathologists perform or oversee testing and interpretation.
208000000X	Clinical Laboratory	Clinical laboratory scientists and directors manage technical test performance.
2084P0800X	Psychiatry & Neurology	Psychiatrists order tests for antidepressant monitoring and interpret results for medication management.

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`F32.1`	Major depressive disorder, single episode, moderate	Common indication for monitoring antidepressant adherence and therapeutic levels.
`F33.1`	Major depressive disorder, recurrent, moderate	Used when assessing ongoing antidepressant therapy efficacy and adherence.
`F32.9`	Major depressive disorder, single episode, unspecified	General diagnostic category prompting drug level monitoring when treatment response or toxicity concerns exist.
`F41.1`	Generalized anxiety disorder	Antidepressants may be prescribed; testing can assess adherence or unexpected levels.
`T43.0X5A`	Poisoning by tricyclic and tetracyclic antidepressants, accidental (initial encounter)	Relevant when evaluating suspected overdose or toxicity involving tricyclic agents.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`80335`	Toxicology testing, tricyclic and other cyclical antidepressants; qualitative or quantitative, single or multiple analytes for one or two drugs	Primary assay to detect/measure tricyclic and cyclical antidepressants in patient specimens.
`80307`	Drug testing, presumptive, any number of drug classes; any number of devices or procedures, single or multiplex	May be used as initial broad-screen toxicology before specific antidepressant confirmation.
`80306`	Drug testing, presumptive, any number of drug classes; multiple drug class screen	Used for initial point-of-care or lab-based screening for many drug classes including antidepressants.
`80320`	Drug confirmation by chromatography, qualitative or quantitative, each specimen	Used when confirmation of antidepressant presence/levels is required after screening; often LC-MS/MS or GC-MS.
`80318`	Drug testing, confirmatory; each specimen	Alternative confirmatory code for quantitation/confirmation methods following presumptive testing.

Related Codes

CPT-80320-ALCOHOL-DETECTION-IN-SPECIMEN

CPT 80320: Alcohol Detection in Patient Specimens

CPT-80321-ALCOHOL-BIOMARKER-ASSAY

CPT 80321: Alcohol Biomarker Detection and Measurement

CPT-80322-ALCOHOL-BIOMARKER-PANEL-MULTI-ANALYTE

CPT 80322: Alcohol Biomarker Panel, Multi-Analyte

CPT-80323-ALKALOID-DRUG-LEVEL-ANALYSIS

CPT 80323: Alkaloid Drug Level Analysis

CPT-80324-AMPHETAMINE-DRUG-TESTING-LAB-ASSAY

CPT 80324: Amphetamine Detection/Quantification in Patient Specimen

CPT-80325-AMPHETAMINES-DETECTION-AND-QUANTIFICATION

CPT 80325: Amphetamines Detection and Quantification

CPT-80326-AMPHETAMINES-PANEL-5-OR-MORE

CPT 80326: Multi‑Amphetamine Toxicology Panel

CPT-80334-SEROTONERGIC-ANTIDEPRESSANT-PANEL

CPT 80334: Multi-Analyte Serotonergic Antidepressant Panel

CPT-80344-MULTI-ANTIPSYCHOTIC-PANEL-SEVEN-PLUS-DRUGS

CPT 80344: Multi‑analyte Antipsychotic Test, Seven or More Drugs

CPT-80345-BARBITURATE-DETECTION-SERUM-URINE

CPT 80345: Barbiturate Detection in Serum or Urine

Showing 1–10 of 24

Frequently Asked Questions

References

1.CPT® Codes and Descriptions. AAPC. Retrieved Jul 29, 2026.
2.HCPCS Quarterly Update. Centers for Medicare & Medicaid Services (CMS). Retrieved Jul 29, 2026.
3.ICD-10-CM Full Code List. Centers for Medicare & Medicaid Services (CMS). Retrieved Jul 29, 2026.

Published by

Trek Health powers OpenPayer with a leading commercial payer intelligence platform, seamlessly converting fragmented payer data into actionable insights for provider organizations.

Trek Health ingests and normalizes Transparency in Coverage data and payer policy updates to give provider organizations a clear view of how commercial reimbursement behaves across markets, payers, and services. Our platform transforms raw payer disclosures into structured intelligence that supports contract evaluation, payer negotiations, and service line strategy. By combining market benchmarks with ongoing policy visibility, Trek helps teams identify variability, risk, and opportunity in commercial reimbursement. The result is faster insight, stronger negotiating positions, and more informed financial decisions.

Clinical & Coding Specifications

Clinical Context

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`	Technical component	Use when billing only the technical component (laboratory equipment, supplies, and technician work) for the test.
`90`	Reference (outside) laboratory	Use when test performed by an outside reference laboratory and the submitting provider bills for the service.
`91`	Repeat clinical diagnostic laboratory test	Use when the same test is repeated on the same day to obtain subsequent test results.
`52`	Reduced services	Use if the laboratory performs a reduced service relative to the full test procedure.
`53`	Discontinued procedure	Use when the test process was started but discontinued for clinical reasons.
`59`	Unbundling distinct procedural service	Not in the provided list; excluded.
`90` (duplicate)	See above	See above
`91` (duplicate)	See above	See above
`QX`	Modifier for certified nurse-midwife	Use only when applicable to non-physician practitioner billing relationships (rare for lab billing).
`QY`	CRNA service with medical direction	Use only when applicable to anesthesia supervision (generally not applicable).
`AS`	Physician assistant services	Use when a physician assistant furnishes services that are payable under the PA taxonomy and billing rules.

Taxonomy Code	Specialty	Notes
208D00000X	Pathology & Laboratory Medicine	Laboratories and pathologists perform or oversee testing and interpretation.
208000000X	Clinical Laboratory	Clinical laboratory scientists and directors manage technical test performance.
2084P0800X	Psychiatry & Neurology	Psychiatrists order tests for antidepressant monitoring and interpret results for medication management.

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`F32.1`	Major depressive disorder, single episode, moderate	Common indication for monitoring antidepressant adherence and therapeutic levels.
`F33.1`	Major depressive disorder, recurrent, moderate	Used when assessing ongoing antidepressant therapy efficacy and adherence.
`F32.9`	Major depressive disorder, single episode, unspecified	General diagnostic category prompting drug level monitoring when treatment response or toxicity concerns exist.
`F41.1`	Generalized anxiety disorder	Antidepressants may be prescribed; testing can assess adherence or unexpected levels.
`T43.0X5A`	Poisoning by tricyclic and tetracyclic antidepressants, accidental (initial encounter)	Relevant when evaluating suspected overdose or toxicity involving tricyclic agents.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`80335`	Toxicology testing, tricyclic and other cyclical antidepressants; qualitative or quantitative, single or multiple analytes for one or two drugs	Primary assay to detect/measure tricyclic and cyclical antidepressants in patient specimens.
`80307`	Drug testing, presumptive, any number of drug classes; any number of devices or procedures, single or multiplex	May be used as initial broad-screen toxicology before specific antidepressant confirmation.
`80306`	Drug testing, presumptive, any number of drug classes; multiple drug class screen	Used for initial point-of-care or lab-based screening for many drug classes including antidepressants.
`80320`	Drug confirmation by chromatography, qualitative or quantitative, each specimen	Used when confirmation of antidepressant presence/levels is required after screening; often LC-MS/MS or GC-MS.
`80318`	Drug testing, confirmatory; each specimen	Alternative confirmatory code for quantitation/confirmation methods following presumptive testing.

Related Codes

CPT-80320-ALCOHOL-DETECTION-IN-SPECIMEN

CPT 80320: Alcohol Detection in Patient Specimens

CPT-80321-ALCOHOL-BIOMARKER-ASSAY

CPT 80321: Alcohol Biomarker Detection and Measurement

CPT-80322-ALCOHOL-BIOMARKER-PANEL-MULTI-ANALYTE

CPT 80322: Alcohol Biomarker Panel, Multi-Analyte

CPT-80323-ALKALOID-DRUG-LEVEL-ANALYSIS

CPT 80323: Alkaloid Drug Level Analysis

CPT-80324-AMPHETAMINE-DRUG-TESTING-LAB-ASSAY

CPT 80324: Amphetamine Detection/Quantification in Patient Specimen

CPT-80325-AMPHETAMINES-DETECTION-AND-QUANTIFICATION

CPT 80325: Amphetamines Detection and Quantification

CPT-80326-AMPHETAMINES-PANEL-5-OR-MORE

CPT 80326: Multi‑Amphetamine Toxicology Panel

CPT-80334-SEROTONERGIC-ANTIDEPRESSANT-PANEL

CPT 80334: Multi-Analyte Serotonergic Antidepressant Panel

CPT-80344-MULTI-ANTIPSYCHOTIC-PANEL-SEVEN-PLUS-DRUGS

CPT 80344: Multi‑analyte Antipsychotic Test, Seven or More Drugs

CPT-80345-BARBITURATE-DETECTION-SERUM-URINE

CPT 80345: Barbiturate Detection in Serum or Urine

Showing 1–10 of 24

Frequently Asked Questions

References

1.CPT® Codes and Descriptions. AAPC. Retrieved Jul 29, 2026.
2.HCPCS Quarterly Update. Centers for Medicare & Medicaid Services (CMS). Retrieved Jul 29, 2026.
3.ICD-10-CM Full Code List. Centers for Medicare & Medicaid Services (CMS). Retrieved Jul 29, 2026.

Published by

Trek Health powers OpenPayer with a leading commercial payer intelligence platform, seamlessly converting fragmented payer data into actionable insights for provider organizations.

OpenPayer

CPT 80335: Assay for Tricyclic and Cyclical Antidepressants

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Billing Code Overview

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OpenPayer

CPT 80335: Assay for Tricyclic and Cyclical Antidepressants

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Billing Code Overview

Clinical & Coding Specifications

Clinical Context

Coding Specifications

Related Diagnoses

Related CPT Codes

Related Codes

References

Clinical & Coding Specifications

Clinical Context

Coding Specifications

Related Diagnoses

Related CPT Codes

Related Codes

References

CPT 80335: Assay for Tricyclic and Cyclical Antidepressants

Sign up for cpt 80335 policy alerts

Billing Code Overview

CPT 80335: Assay for Tricyclic and Cyclical Antidepressants

Sign up for cpt 80335 policy alerts

Billing Code Overview

Clinical & Coding Specifications

Clinical Context

Coding Specifications

Related Diagnoses

Related CPT Codes

Related Codes

What does CPT 80335 describe and when is it used?

Where is 80335 typically performed and what is the usual clinical workflow?

Which billing modifiers are relevant for reporting CPT 80335?

How does 80335 relate to other toxicology CPT codes listed?

What diagnoses commonly justify ordering CPT 80335?

References

Clinical & Coding Specifications

Clinical Context

Coding Specifications

Related Diagnoses

Related CPT Codes

Related Codes

What does CPT 80335 describe and when is it used?

Where is 80335 typically performed and what is the usual clinical workflow?

Which billing modifiers are relevant for reporting CPT 80335?

How does 80335 relate to other toxicology CPT codes listed?

What diagnoses commonly justify ordering CPT 80335?

References