CPT 80235: Lacosamide Quantitative Assay

CPT code 80235 describes a clinical laboratory test in which a lab analyst performs the technical assay to quantify lacosamide levels in a patient specimen; this is a therapeutic drug monitoring service typically performed by a clinical laboratory (service type: toxicology/therapeutic drug monitoring) and commonly provided in hospital or reference laboratory settings or outpatient laboratory collection sites.

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CPT 80235: Lacosamide Quantitative Assay

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Get alerted when payer policies referencing 80235 are released or updated.

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Clinical & Coding Specifications

Clinical Context

A 32-year-old patient with partial-onset seizures managed on lacosamide presents for routine therapeutic drug monitoring after a recent dose change and intermittent breakthrough focal seizures. A clinician orders a serum lacosamide level to assess adherence and therapeutic concentration. A phlebotomy technician collects a blood sample in the outpatient laboratory or hospital inpatient setting; the specimen is sent to the clinical chemistry laboratory. A laboratory analyst performs the quantitative assay for lacosamide (CPT 80235) using validated methods (e.g., LC-MS/MS or immunoassay), documents the assay result in the laboratory information system, and the result is routed to the ordering neurologist. Typical sites of service include outpatient hospitals, independent clinical laboratories, and hospital inpatient laboratories. Turnaround time varies by clinical need: routine levels within 24–72 hours, stat levels within hours. The test is used to confirm therapeutic dosing, evaluate suspected toxicity, assess adherence, and guide medication adjustments when combined with clinical assessment and other monitoring (e.g., drug–drug interactions).

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`80307`	Drug assay, qualitative or semiquantitative, single drug class method (e.g., immunoassay), urine	May be performed alongside serum quantification to screen for multiple drugs or adherence in urine when clinical context requires broader toxicology screening.
`80311`	Drug confirmation, quantitative, by definitive technology (e.g., GC/MS, LC/MS/MS), single drug	Used for definitive confirmation of drug levels or when a different method is required; similar analytical platforms may be used for lacosamide quantification.
`80500`	Drug assay, quantitative, single drug (e.g., serum, plasma)	Generic quantitative drug assay category; related when labs bill a specific quantitative assay for therapeutic drug monitoring.
`36415`	Collection of venous blood by venipuncture	Often performed immediately prior to the assay as the specimen collection procedure.
`99000`	Handling and/or conveyance of specimen (used historically)	Administrative or specimen handling codes in some billing systems relate to logistics of specimen transport to the performing laboratory.

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…
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…
91	Modifier 91 — “Repeat Clinical Diagnostic Laboratory Test” — is appended when the exact same CPT laboratory test is performed more than once for the same patient on the same day because serial,…	- Use modifier 91 when the exact same CPT laboratory test is performed more than once on the same patient on the same date because serial or repeated testing is medically necessary to monitor…
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…

Related Provider Taxonomies

8 rows

Taxonomy Code	Specialty	Notes
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…
2080P0207X	Pediatric Hematology & Oncology Physician	A pediatrician trained in the combination of pediatrics, hematology and oncology to recognize and manage pediatric blood disorders and cancerous disea…
363A00000X	Physician Assistant	A physician assistant is a person who has successfully completed an accredited education program for physician assistant, is licensed by the state and…
207LP2900X	Pain Medicine (Anesthesiology) Physician	An anesthesiologist who provides a high level of care, either as a primary physician or consultant, for patients experiencing problems with acute, chr…
261QR0404X	Cardiac Rehabilitation Clinic/Center	Ambulatory Health Care Facilities · Clinic/Center
246XC2903X	Vascular Specialist/Technologist Cardiovascular	A vascular technologist, also known as a vascular sonographer, creates images of blood vessels and collects data that help physicians diagnose disorde…
208VP0014X	Interventional Pain Medicine Physician	Interventional Pain Medicine is the discipline of medicine devoted to the diagnosis and treatment of pain and related disorders principally with the a…

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.

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Clinical & Coding Specifications

Clinical Context

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`80307`	Drug assay, qualitative or semiquantitative, single drug class method (e.g., immunoassay), urine	May be performed alongside serum quantification to screen for multiple drugs or adherence in urine when clinical context requires broader toxicology screening.
`80311`	Drug confirmation, quantitative, by definitive technology (e.g., GC/MS, LC/MS/MS), single drug	Used for definitive confirmation of drug levels or when a different method is required; similar analytical platforms may be used for lacosamide quantification.
`80500`	Drug assay, quantitative, single drug (e.g., serum, plasma)	Generic quantitative drug assay category; related when labs bill a specific quantitative assay for therapeutic drug monitoring.
`36415`	Collection of venous blood by venipuncture	Often performed immediately prior to the assay as the specimen collection procedure.
`99000`	Handling and/or conveyance of specimen (used historically)	Administrative or specimen handling codes in some billing systems relate to logistics of specimen transport to the performing laboratory.

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…
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…
91	Modifier 91 — “Repeat Clinical Diagnostic Laboratory Test” — is appended when the exact same CPT laboratory test is performed more than once for the same patient on the same day because serial,…	- Use modifier 91 when the exact same CPT laboratory test is performed more than once on the same patient on the same date because serial or repeated testing is medically necessary to monitor…
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…

Related Provider Taxonomies

8 rows

Taxonomy Code	Specialty	Notes
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…
2080P0207X	Pediatric Hematology & Oncology Physician	A pediatrician trained in the combination of pediatrics, hematology and oncology to recognize and manage pediatric blood disorders and cancerous disea…
363A00000X	Physician Assistant	A physician assistant is a person who has successfully completed an accredited education program for physician assistant, is licensed by the state and…
207LP2900X	Pain Medicine (Anesthesiology) Physician	An anesthesiologist who provides a high level of care, either as a primary physician or consultant, for patients experiencing problems with acute, chr…
261QR0404X	Cardiac Rehabilitation Clinic/Center	Ambulatory Health Care Facilities · Clinic/Center
246XC2903X	Vascular Specialist/Technologist Cardiovascular	A vascular technologist, also known as a vascular sonographer, creates images of blood vessels and collects data that help physicians diagnose disorde…
208VP0014X	Interventional Pain Medicine Physician	Interventional Pain Medicine is the discipline of medicine devoted to the diagnosis and treatment of pain and related disorders principally with the a…

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 80235: Lacosamide Quantitative Assay

Sign up for cpt 80235 policy alerts

OpenPayer

CPT 80235: Lacosamide Quantitative Assay

Sign up for cpt 80235 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 80235: Lacosamide Quantitative Assay

Sign up for cpt 80235 policy alerts

CPT 80235: Lacosamide Quantitative Assay

Sign up for cpt 80235 policy alerts

Clinical & Coding Specifications

Clinical Context

Related CPT Codes

Related Modifiers

Related Provider Taxonomies

Related Codes

What does CPT 80235 represent and in what clinical context is it used?

Which billing modifiers are commonly relevant to CPT 80235 and when should they be applied?

Where is the lacosamide quantitative assay usually performed and what are typical turnaround times?

What related CPT codes might appear on the same claim as CPT 80235?

Which diagnoses are typically associated with ordering CPT 80235 for lacosamide levels?

References

Clinical & Coding Specifications

Clinical Context

Related CPT Codes

Related Modifiers

Related Provider Taxonomies

Related Codes

What does CPT 80235 represent and in what clinical context is it used?

Which billing modifiers are commonly relevant to CPT 80235 and when should they be applied?

Where is the lacosamide quantitative assay usually performed and what are typical turnaround times?

What related CPT codes might appear on the same claim as CPT 80235?

Which diagnoses are typically associated with ordering CPT 80235 for lacosamide levels?

References