CPT 80175: Lamotrigine Level Assay

CPT code 80175 describes a laboratory test that measures the lamotrigine level in a patient’s specimen, a therapeutic drug monitoring service typically performed by clinical laboratories using blood or serum samples; service type: laboratory therapeutic drug assay; typical site of service: outpatient clinical laboratory or hospital laboratory performing specimen analysis.

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CPT 80175: Lamotrigine Level Assay

Customize your policy alerts

Sign up for cpt 80175 policy alerts

Get alerted when payer policies referencing 80175 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 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.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`80053`	Comprehensive metabolic panel	Performed to evaluate electrolytes, liver and renal function which affect lamotrigine metabolism and dosing decisions
`80061`	Lipid panel	Not directly related but commonly ordered in psychiatric medication monitoring visits for baseline or routine labs
`81002`	Urinalysis, non-automated, without microscopy	May be ordered as part of routine monitoring or to assess hydration or renal status before dose adjustment
`80175`	Lamotrigine level	Quantitative measurement of lamotrigine in serum/plasma — the primary procedure here
`36415`	Collection of venous blood by venipuncture	Specimen collection code commonly billed when blood is drawn for lamotrigine assay
`99000`	Handling and/or conveyance of specimen for transfer from physician to another lab	May apply when specimens are sent to an external reference laboratory for `80175` testing

Related Modifiers

6 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…
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…
63	Modifier‑63 is appended to surgical CPT codes (20000–69990) when a procedure is performed on a neonate or infant weighing ≤ 4 kg (about 8.8 lbs). The AMA/AAPC definition specifies this use and notes…	- Use modifier -63 only for surgical procedures in the CPT 20000–69990 series performed on a neonate or infant who weighs ≤ 4 kg at the time of the procedure; it indicates increased complexity due to…

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, …
2084P0805X	Geriatric Psychiatry Physician	Geriatric Psychiatry is a subspecialty with psychiatric expertise in prevention, evaluation, diagnosis and treatment of mental and emotional disorders…
2084N0400X	Neurology Physician	A Neurologist specializes in the diagnosis and treatment of diseases or impaired function of the brain, spinal cord, peripheral nerves, muscles, auton…
207R00000X	Internal Medicine Physician	A physician who provides long-term, comprehensive care in the office and the hospital, managing both common and complex illness of adolescents, adults…
246ZN0300X	Nephrology Specialist/Technologist	Technologists, Technicians & Other Technical Service Providers · Specialist/Technologist, Other
207VC0200X	Critical Care Medicine (Obstetrics & Gynecology) Physician	An obstetrician/gynecologist, who specializes in critical care medicine diagnoses, treats and supports female patients with multiple organ dysfunction…
2080S0010X	Pediatric Sports Medicine Physician	A pediatrician who is responsible for continuous care in the field of sports medicine, not only for the enhancement of health and fitness, but also fo…
207UN0902X	Nuclear Imaging & Therapy Physician	A nuclear medicine physician who specializes in nuclear imaging and therapy.

Related ICD-10-CM Codes

25 rows

ICD-10-CM Code	Description
F06.8	Other specified mental disorders due to known physiological condition
F10.20	Alcohol dependence, uncomplicated
F11.20	Opioid dependence, uncomplicated
F20.9	Schizophrenia, unspecified
F33.1	Major depressive disorder, recurrent, moderate
F41.1	Generalized anxiety disorder
F90.0	Attention-deficit hyperactivity disorder, predominantly inattentive type
G25.0	Essential tremor
G25.4	Drug-induced chorea
G40.101	Localization-related (focal) (partial) symptomatic epilepsy and epileptic syndromes with simple partial seizures, not intractable, with status epilepticus

Showing 1–10 of 25

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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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.

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Clinical & Coding Specifications

Clinical Context

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`80053`	Comprehensive metabolic panel	Performed to evaluate electrolytes, liver and renal function which affect lamotrigine metabolism and dosing decisions
`80061`	Lipid panel	Not directly related but commonly ordered in psychiatric medication monitoring visits for baseline or routine labs
`81002`	Urinalysis, non-automated, without microscopy	May be ordered as part of routine monitoring or to assess hydration or renal status before dose adjustment
`80175`	Lamotrigine level	Quantitative measurement of lamotrigine in serum/plasma — the primary procedure here
`36415`	Collection of venous blood by venipuncture	Specimen collection code commonly billed when blood is drawn for lamotrigine assay
`99000`	Handling and/or conveyance of specimen for transfer from physician to another lab	May apply when specimens are sent to an external reference laboratory for `80175` testing

Related Modifiers

6 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…
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…
63	Modifier‑63 is appended to surgical CPT codes (20000–69990) when a procedure is performed on a neonate or infant weighing ≤ 4 kg (about 8.8 lbs). The AMA/AAPC definition specifies this use and notes…	- Use modifier -63 only for surgical procedures in the CPT 20000–69990 series performed on a neonate or infant who weighs ≤ 4 kg at the time of the procedure; it indicates increased complexity due to…

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, …
2084P0805X	Geriatric Psychiatry Physician	Geriatric Psychiatry is a subspecialty with psychiatric expertise in prevention, evaluation, diagnosis and treatment of mental and emotional disorders…
2084N0400X	Neurology Physician	A Neurologist specializes in the diagnosis and treatment of diseases or impaired function of the brain, spinal cord, peripheral nerves, muscles, auton…
207R00000X	Internal Medicine Physician	A physician who provides long-term, comprehensive care in the office and the hospital, managing both common and complex illness of adolescents, adults…
246ZN0300X	Nephrology Specialist/Technologist	Technologists, Technicians & Other Technical Service Providers · Specialist/Technologist, Other
207VC0200X	Critical Care Medicine (Obstetrics & Gynecology) Physician	An obstetrician/gynecologist, who specializes in critical care medicine diagnoses, treats and supports female patients with multiple organ dysfunction…
2080S0010X	Pediatric Sports Medicine Physician	A pediatrician who is responsible for continuous care in the field of sports medicine, not only for the enhancement of health and fitness, but also fo…
207UN0902X	Nuclear Imaging & Therapy Physician	A nuclear medicine physician who specializes in nuclear imaging and therapy.

Related ICD-10-CM Codes

25 rows

ICD-10-CM Code	Description
F06.8	Other specified mental disorders due to known physiological condition
F10.20	Alcohol dependence, uncomplicated
F11.20	Opioid dependence, uncomplicated
F20.9	Schizophrenia, unspecified
F33.1	Major depressive disorder, recurrent, moderate
F41.1	Generalized anxiety disorder
F90.0	Attention-deficit hyperactivity disorder, predominantly inattentive type
G25.0	Essential tremor
G25.4	Drug-induced chorea
G40.101	Localization-related (focal) (partial) symptomatic epilepsy and epileptic syndromes with simple partial seizures, not intractable, with status epilepticus

Showing 1–10 of 25

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 80175: Lamotrigine Level Assay

Sign up for cpt 80175 policy alerts

OpenPayer

CPT 80175: Lamotrigine Level Assay

Sign up for cpt 80175 policy alerts

Clinical & Coding Specifications

Clinical Context

Related CPT Codes

Related Modifiers

Related Provider Taxonomies

Related ICD-10-CM Codes

Related Codes

References

Clinical & Coding Specifications

Clinical Context

Related CPT Codes

Related Modifiers

Related Provider Taxonomies

Related ICD-10-CM Codes

Related Codes

References

CPT 80175: Lamotrigine Level Assay

Sign up for cpt 80175 policy alerts

CPT 80175: Lamotrigine Level Assay

Sign up for cpt 80175 policy alerts

Clinical & Coding Specifications

Clinical Context

Related CPT Codes

Related Modifiers

Related Provider Taxonomies

Related ICD-10-CM Codes

Related Codes

What does CPT 80175 represent and when is it typically used?

Which billing modifiers are commonly used with 80175 and what do they indicate?

Where is the lamotrigine level test performed and where are specimens commonly collected?

What other CPT codes are often billed alongside 80175?

In what clinical situations is a lamotrigine level (80175) ordered?

References

Clinical & Coding Specifications

Clinical Context

Related CPT Codes

Related Modifiers

Related Provider Taxonomies

Related ICD-10-CM Codes

Related Codes

What does CPT 80175 represent and when is it typically used?

Which billing modifiers are commonly used with 80175 and what do they indicate?

Where is the lamotrigine level test performed and where are specimens commonly collected?

What other CPT codes are often billed alongside 80175?

In what clinical situations is a lamotrigine level (80175) ordered?

References