CPT 80181: Flecainide Quantitative Serum Assay

CPT code 80181 describes a quantitative laboratory assay performed by a lab analyst to measure flecainide concentration in a patient specimen (for example, serum); this service is a clinical pharmacology/toxicology test typically performed as a technical laboratory procedure in an ambulatory or hospital clinical laboratory setting to guide management of patients on Class I antiarrhythmic therapy.

Customize your policy alerts

Sign up for cpt 80181 policy alerts

Get alerted when payer policies referencing 80181 are released or updated.

Monitor payer policy activity

Receive email alerts as soon as relevant payer policies are published or updated.

Explore openpayer tools

View all tools

CPT 80181: Flecainide Quantitative Serum Assay

Customize your policy alerts

Sign up for cpt 80181 policy alerts

Get alerted when payer policies referencing 80181 are released or updated.

Monitor payer policy activity

Receive email alerts as soon as relevant payer policies are published or updated.

Clinical & Coding Specifications

Clinical Context

A typical patient is an adult with a history of life‑threatening ventricular arrhythmias who is receiving flecainide for rhythm control. The patient presents to an outpatient or inpatient clinical laboratory for therapeutic drug monitoring when there is concern for toxicity, treatment failure, a medication change, potential drug–drug interaction, renal or hepatic dysfunction, or dose adjustment after a change in clinical status. A blood specimen (serum or plasma) is collected by a phlebotomist or nursing staff and sent to the hospital or reference laboratory. The laboratory analyst performs the technical assay to quantify flecainide concentration (80181). Results are reviewed by the clinical laboratory director and released to the ordering cardiologist, electrophysiologist, or inpatient team for interpretation in the context of symptoms, ECG findings, and concomitant medications. Typical sites of service include hospital outpatient laboratory, inpatient hospital laboratory, and independent clinical reference laboratories; the test may be ordered from cardiology clinics, emergency departments, or inpatient services.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`80053`	Comprehensive metabolic panel	Used to assess renal and hepatic function that affect flecainide clearance and dosing
`84443`	Thyroid stimulating hormone (TSH)	Thyroid status can affect arrhythmia management and may be ordered in workup of arrhythmias
`93000`	Electrocardiogram, routine ECG with at least 12 leads; with interpretation and report	Performed to correlate flecainide levels with ECG changes and arrhythmia status
`93010`	Interpretation and report only for ECG	When ECG interpretation is billed separately from ECG performance
`36415`	Collection of venous blood by venipuncture	Phlebotomy procedure to obtain the specimen for flecainide assay
`80181`	Flecainide level, quantitation (the index code)	The laboratory technical assay to quantify flecainide in patient serum or plasma

Related Modifiers

5 rows

Modifier	Description	When to Use
26	Modifier 26 (Professional Component) identifies and bills only the professional portion of a split service — the physician’s interpretation, report, and medical judgment — when the technical…	- Use CPT Modifier -26 when you are billing only the professional component (PC) of a split‑bill eligible service—i.e., you performed the physician interpretation, medical judgment and prepared a…
52	Modifier ‑52 (Reduced Services) indicates that a service or procedure was partially reduced or omitted at the provider’s discretion, allowing reporting of the basic procedure number with a qualifier…	- Use modifier -52 when a physician or qualified health professional electively reduces or omits part of a procedure or service (for example, performing fewer required views or omitting a portion of…
53	Modifier 53 (Discontinued Procedure) signals that a surgical or diagnostic service was begun by the physician but terminated because of extenuating circumstances that threatened the patient’s…	- Use modifier -53 when a physician/qualified healthcare professional has started a surgical or diagnostic procedure (e.g., anesthesia administered, incision or scope insertion) and then discontinues…
59	Modifier 59 indicates a distinct procedural service when two procedures that are not normally billed together are clinically and procedurally separate. The CPT definition (as reiterated by CMS)…	- Use modifier -59 to report a distinct procedural service when documentation supports that the procedure reported is not normally billed together with another service on the same day because of a…
90	Modifier ‑90 (Reference/Outside Laboratory) indicates that a laboratory test was performed by an entity other than the treating or reporting provider. The American Medical Association defines…	- Use CPT modifier -90 when a laboratory test is performed by an outside/reference laboratory (an entity other than the treating or reporting physician or qualified professional) and the claim needs…

Related Provider Taxonomies

8 rows

Taxonomy Code	Specialty	Notes
2084P0800X	Psychiatry Physician	A Psychiatrist specializes in the prevention, diagnosis, and treatment of mental disorders, emotional disorders, psychotic disorders, mood disorders, …
207RH0000X	Hematology (Internal Medicine) Physician	An internist with additional training who specializes in diseases of the blood, spleen and lymph. This specialist treats conditions such as anemia, cl…
207L00000X	Anesthesiology Physician	An anesthesiologist is trained to provide pain relief and maintenance, or restoration, of a stable condition during and immediately following an opera…
363LF0000X	Family Nurse Practitioner	Physician Assistants & Advanced Practice Nursing Providers · Nurse Practitioner
207ZB0001X	Blood Banking & Transfusion Medicine Physician	A physician who specializes in blood banking/transfusion medicine is responsible for the maintenance of an adequate blood supply, blood donor and pati…
246Y00000X	Health Information Specialist/Technologist	An individual with a high school diploma, on-the-job experience and coding education from seminars or college classes who passes a national certificat…
283X00000X	Rehabilitation Hospital	A hospital or facility that provides health-related, social and/or vocational services to disabled persons to help them attain their maximum functiona…
163WP0807X	Child & Adolescent Psychiatric/Mental Health Registered Nurse	Nursing Service Providers · Registered Nurse

CPT 80143: Acetaminophen Quantitative Assay

CPT-80145-ADALIMUMAB-LEVEL-ASSAY-THERAPEUTIC-DRUG-MONITORING

CPT 80145: Adalimumab Quantitative Drug Level Assay

CPT-80150-AMIKACIN-QUANTITATIVE-ASSAY-THERAPEUTIC-DRUG-MONITORING

CPT 80150: Amikacin Quantitative Serum Level

CPT-80151-AMIODARONE-QUANTITATIVE-SERUM-ASSAY

CPT 80151: Amiodarone Quantitative Drug Level Assay

CPT-80155-CAFFEINE-LEVEL-TESTING

CPT 80155: Caffeine Level Quantification

CPT-80156-CARBAMAZEPINE-TOTAL-LEVEL-LAB-ASSAY

CPT 80156: Carbamazepine Total Level (Serum)

CPT-80157-FREE-CARBAMAZEPINE-ASSAY

CPT 80157: Free Carbamazepine Quantitative Assay

CPT-80158-CYCLOSPORINE-QUANTITATIVE-ASSAY-LAB

CPT 80158: Cyclosporine Quantitation, Laboratory

CPT-80159-CLOZAPINE-LEVEL-ASSAY-THERAPEUTIC-DRUG-MONITORING

CPT 80159: Clozapine Level Measurement

CPT-80161-CARBAMAZEPINE-EPOXIDE-QUANTITATIVE-ASSAY

CPT 80161: Carbamazepine 10,11-Epoxide Level, Quantitative

Showing 1–10 of 87

Frequently Asked Questions

References

1.CPT® Codes and Descriptions. AAPC. Retrieved Aug 11, 2026.Maintains the CPT code set's official descriptions and guidelines, licensed from the American Medical Association, used as the definitional source for CPT codes on this page.
2.HCPCS Quarterly Update. Centers for Medicare & Medicaid Services (CMS). Retrieved Aug 11, 2026.CMS's quarterly release of HCPCS Level II codes and short/long descriptors, the source for HCPCS code definitions and update history.
3.ICD-10-CM Full Code List. Centers for Medicare & Medicaid Services (CMS). Retrieved Aug 11, 2026.CMS's complete ICD-10-CM diagnosis code list, used to cross-reference diagnosis codes associated with this procedure or service.

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.

Explore openpayer tools

View all tools

Clinical & Coding Specifications

Clinical Context

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`80053`	Comprehensive metabolic panel	Used to assess renal and hepatic function that affect flecainide clearance and dosing
`84443`	Thyroid stimulating hormone (TSH)	Thyroid status can affect arrhythmia management and may be ordered in workup of arrhythmias
`93000`	Electrocardiogram, routine ECG with at least 12 leads; with interpretation and report	Performed to correlate flecainide levels with ECG changes and arrhythmia status
`93010`	Interpretation and report only for ECG	When ECG interpretation is billed separately from ECG performance
`36415`	Collection of venous blood by venipuncture	Phlebotomy procedure to obtain the specimen for flecainide assay
`80181`	Flecainide level, quantitation (the index code)	The laboratory technical assay to quantify flecainide in patient serum or plasma

Related Modifiers

5 rows

Modifier	Description	When to Use
26	Modifier 26 (Professional Component) identifies and bills only the professional portion of a split service — the physician’s interpretation, report, and medical judgment — when the technical…	- Use CPT Modifier -26 when you are billing only the professional component (PC) of a split‑bill eligible service—i.e., you performed the physician interpretation, medical judgment and prepared a…
52	Modifier ‑52 (Reduced Services) indicates that a service or procedure was partially reduced or omitted at the provider’s discretion, allowing reporting of the basic procedure number with a qualifier…	- Use modifier -52 when a physician or qualified health professional electively reduces or omits part of a procedure or service (for example, performing fewer required views or omitting a portion of…
53	Modifier 53 (Discontinued Procedure) signals that a surgical or diagnostic service was begun by the physician but terminated because of extenuating circumstances that threatened the patient’s…	- Use modifier -53 when a physician/qualified healthcare professional has started a surgical or diagnostic procedure (e.g., anesthesia administered, incision or scope insertion) and then discontinues…
59	Modifier 59 indicates a distinct procedural service when two procedures that are not normally billed together are clinically and procedurally separate. The CPT definition (as reiterated by CMS)…	- Use modifier -59 to report a distinct procedural service when documentation supports that the procedure reported is not normally billed together with another service on the same day because of a…
90	Modifier ‑90 (Reference/Outside Laboratory) indicates that a laboratory test was performed by an entity other than the treating or reporting provider. The American Medical Association defines…	- Use CPT modifier -90 when a laboratory test is performed by an outside/reference laboratory (an entity other than the treating or reporting physician or qualified professional) and the claim needs…

Related Provider Taxonomies

8 rows

Taxonomy Code	Specialty	Notes
2084P0800X	Psychiatry Physician	A Psychiatrist specializes in the prevention, diagnosis, and treatment of mental disorders, emotional disorders, psychotic disorders, mood disorders, …
207RH0000X	Hematology (Internal Medicine) Physician	An internist with additional training who specializes in diseases of the blood, spleen and lymph. This specialist treats conditions such as anemia, cl…
207L00000X	Anesthesiology Physician	An anesthesiologist is trained to provide pain relief and maintenance, or restoration, of a stable condition during and immediately following an opera…
363LF0000X	Family Nurse Practitioner	Physician Assistants & Advanced Practice Nursing Providers · Nurse Practitioner
207ZB0001X	Blood Banking & Transfusion Medicine Physician	A physician who specializes in blood banking/transfusion medicine is responsible for the maintenance of an adequate blood supply, blood donor and pati…
246Y00000X	Health Information Specialist/Technologist	An individual with a high school diploma, on-the-job experience and coding education from seminars or college classes who passes a national certificat…
283X00000X	Rehabilitation Hospital	A hospital or facility that provides health-related, social and/or vocational services to disabled persons to help them attain their maximum functiona…
163WP0807X	Child & Adolescent Psychiatric/Mental Health Registered Nurse	Nursing Service Providers · Registered Nurse

CPT 80143: Acetaminophen Quantitative Assay

CPT-80145-ADALIMUMAB-LEVEL-ASSAY-THERAPEUTIC-DRUG-MONITORING

CPT 80145: Adalimumab Quantitative Drug Level Assay

CPT-80150-AMIKACIN-QUANTITATIVE-ASSAY-THERAPEUTIC-DRUG-MONITORING

CPT 80150: Amikacin Quantitative Serum Level

CPT-80151-AMIODARONE-QUANTITATIVE-SERUM-ASSAY

CPT 80151: Amiodarone Quantitative Drug Level Assay

CPT-80155-CAFFEINE-LEVEL-TESTING

CPT 80155: Caffeine Level Quantification

CPT-80156-CARBAMAZEPINE-TOTAL-LEVEL-LAB-ASSAY

CPT 80156: Carbamazepine Total Level (Serum)

CPT-80157-FREE-CARBAMAZEPINE-ASSAY

CPT 80157: Free Carbamazepine Quantitative Assay

CPT-80158-CYCLOSPORINE-QUANTITATIVE-ASSAY-LAB

CPT 80158: Cyclosporine Quantitation, Laboratory

CPT-80159-CLOZAPINE-LEVEL-ASSAY-THERAPEUTIC-DRUG-MONITORING

CPT 80159: Clozapine Level Measurement

CPT-80161-CARBAMAZEPINE-EPOXIDE-QUANTITATIVE-ASSAY

CPT 80161: Carbamazepine 10,11-Epoxide Level, Quantitative

Showing 1–10 of 87

Frequently Asked Questions

References

1.CPT® Codes and Descriptions. AAPC. Retrieved Aug 11, 2026.Maintains the CPT code set's official descriptions and guidelines, licensed from the American Medical Association, used as the definitional source for CPT codes on this page.
2.HCPCS Quarterly Update. Centers for Medicare & Medicaid Services (CMS). Retrieved Aug 11, 2026.CMS's quarterly release of HCPCS Level II codes and short/long descriptors, the source for HCPCS code definitions and update history.
3.ICD-10-CM Full Code List. Centers for Medicare & Medicaid Services (CMS). Retrieved Aug 11, 2026.CMS's complete ICD-10-CM diagnosis code list, used to cross-reference diagnosis codes associated with this procedure or service.

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 80181: Flecainide Quantitative Serum Assay

Sign up for cpt 80181 policy alerts

OpenPayer

CPT 80181: Flecainide Quantitative Serum Assay

Sign up for cpt 80181 policy alerts

Clinical & Coding Specifications

Clinical Context

Related CPT Codes

Related Modifiers

Related Provider Taxonomies

Related Codes

References

Clinical & Coding Specifications

Clinical Context

Related CPT Codes

Related Modifiers

Related Provider Taxonomies

Related Codes

References

CPT 80181: Flecainide Quantitative Serum Assay

Sign up for cpt 80181 policy alerts

CPT 80181: Flecainide Quantitative Serum Assay

Sign up for cpt 80181 policy alerts

Clinical & Coding Specifications

Clinical Context

Related CPT Codes

Related Modifiers

Related Provider Taxonomies

Related Codes

What does CPT code 80181 describe and when is it typically ordered?

Where is the flecainide quantitative assay usually performed and where is it ordered from?

Which billing modifiers are commonly associated with 80181 and when might they apply?

What other tests are often ordered with the flecainide level (80181) and why?

For which clinical indications or diagnoses is flecainide level testing relevant?

References

Clinical & Coding Specifications

Clinical Context

Related CPT Codes

Related Modifiers

Related Provider Taxonomies

Related Codes

What does CPT code 80181 describe and when is it typically ordered?

Where is the flecainide quantitative assay usually performed and where is it ordered from?

Which billing modifiers are commonly associated with 80181 and when might they apply?

What other tests are often ordered with the flecainide level (80181) and why?

For which clinical indications or diagnoses is flecainide level testing relevant?

References