CPT 80171: Gabapentin Quantitative Assay, Serum or Plasma

CPT code 80171 describes a laboratory test in which the analyst measures the amount of gabapentin in blood, serum, or plasma; the service is a therapeutic drug monitoring quantitative assay typically performed in a clinical laboratory or hospital lab setting to assess drug levels for seizure management.

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CPT 80171: Gabapentin Quantitative Assay, Serum or Plasma

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Get alerted when payer policies referencing 80171 are released or updated.

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

Clinical & Coding Specifications

Clinical Context

A 34-year-old patient with a history of focal epilepsy is managed in an outpatient neurology clinic. The treating neurologist prescribes gabapentin for seizure control and schedules periodic therapeutic drug monitoring to confirm adherence and to ensure serum concentrations are within the expected range for clinical effect and safety. The patient presents to the outpatient laboratory for a blood draw. A phlebotomist collects a serum sample, which is sent to the clinical chemistry laboratory. The lab analyst performs quantitative measurement of gabapentin in the serum using a validated assay (e.g., liquid chromatography–mass spectrometry or immunoassay), documents the result in the laboratory information system, and reports the value to the ordering clinician. Results are used by the neurologist to adjust gabapentin dosing, evaluate potential toxicity, or assess adherence when seizures are not controlled.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`80171`	Gabapentin; assay of serum, plasma or blood (quantitative)	This is the primary code describing the quantitative measurement of gabapentin concentration in patient serum/plasma.
`36415`	Collection of venous blood by venipuncture	Often performed immediately before laboratory measurement to obtain the specimen for `80171`.
`99000`	Handling and/or conveyance of specimen for transfer to another institution	Used if the specimen requires courier or special handling to an external reference laboratory performing `80171`.
`87426`	Infectious agent antigen detection methods (example unrelated assay)	Not directly related clinically; included here only if additional laboratory testing is performed concurrently.
`82306`	Assay of therapeutic drug level, e.g., valproic acid; other anticonvulsant levels (example analogous)	Other therapeutic drug monitoring codes commonly performed in the same clinical workflow for patients on multiple antiepileptic drugs.

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…
3P	The CPT Category II modifier -3P denotes a performance‑measure exclusion when a required quality action was not performed because of system‑level constraints. It is appended only to Category II…	- When to apply: Use CPT Category II modifier 3P only with Category II (‘‘F’’) codes when a specific quality measure’s specifications allow a system‑level exclusion — append 3P to indicate the…
[object Object]
96	Modifier 96 is appended to CPT codes to indicate that a service or procedure was provided for habilitative purposes — i.e., to help a patient learn, maintain, or improve skills and functioning for…	- Use modifier -96 when a procedure or service that could be either habilitative or rehabilitative is provided specifically for habilitative purposes — i.e., to help a patient learn, maintain, or…

Related Provider Taxonomies

8 rows

Taxonomy Code	Specialty	Notes
207Q00000X	Family Medicine Physician	Family Medicine is the medical specialty which is concerned with the total health care of the individual and the family. It is the specialty in breadt…
363L00000X	Nurse Practitioner	(1) A registered nurse provider with a graduate degree in nursing prepared for advanced practice involving independent and interdependent decision mak…
363LF0000X	Family Nurse Practitioner	Physician Assistants & Advanced Practice Nursing Providers · Nurse Practitioner
261QA3000X	Augmentative Communication Clinic/Center	An entity, facility, or distinct part of a facility staffed by audiology and/or speech professionals with special training in the evaluation of a pati…
251G00000X	Community Based Hospice Care Agency	Agencies · Hospice Care, Community Based
2085R0205X	Radiological Physics Physician	A radiological physicist deals with the diagnostic and therapeutic applications of roentgen rays, gamma rays from sealed sources, ultrasonic radiation…
344800000X	Air Carrier	An air company that the Federal Aviation Administration, the certificate-holding district office (CHDO), regional Flight Standards Division (RFSD) off…
225XE0001X	Environmental Modification Occupational Therapist	Occupational therapy practitioners are experts at identifying the cause of difficulties in performance of activities of daily living and instrumental …

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
`80171`	Gabapentin; assay of serum, plasma or blood (quantitative)	This is the primary code describing the quantitative measurement of gabapentin concentration in patient serum/plasma.
`36415`	Collection of venous blood by venipuncture	Often performed immediately before laboratory measurement to obtain the specimen for `80171`.
`99000`	Handling and/or conveyance of specimen for transfer to another institution	Used if the specimen requires courier or special handling to an external reference laboratory performing `80171`.
`87426`	Infectious agent antigen detection methods (example unrelated assay)	Not directly related clinically; included here only if additional laboratory testing is performed concurrently.
`82306`	Assay of therapeutic drug level, e.g., valproic acid; other anticonvulsant levels (example analogous)	Other therapeutic drug monitoring codes commonly performed in the same clinical workflow for patients on multiple antiepileptic drugs.

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…
3P	The CPT Category II modifier -3P denotes a performance‑measure exclusion when a required quality action was not performed because of system‑level constraints. It is appended only to Category II…	- When to apply: Use CPT Category II modifier 3P only with Category II (‘‘F’’) codes when a specific quality measure’s specifications allow a system‑level exclusion — append 3P to indicate the…
[object Object]
96	Modifier 96 is appended to CPT codes to indicate that a service or procedure was provided for habilitative purposes — i.e., to help a patient learn, maintain, or improve skills and functioning for…	- Use modifier -96 when a procedure or service that could be either habilitative or rehabilitative is provided specifically for habilitative purposes — i.e., to help a patient learn, maintain, or…

Related Provider Taxonomies

8 rows

Taxonomy Code	Specialty	Notes
207Q00000X	Family Medicine Physician	Family Medicine is the medical specialty which is concerned with the total health care of the individual and the family. It is the specialty in breadt…
363L00000X	Nurse Practitioner	(1) A registered nurse provider with a graduate degree in nursing prepared for advanced practice involving independent and interdependent decision mak…
363LF0000X	Family Nurse Practitioner	Physician Assistants & Advanced Practice Nursing Providers · Nurse Practitioner
261QA3000X	Augmentative Communication Clinic/Center	An entity, facility, or distinct part of a facility staffed by audiology and/or speech professionals with special training in the evaluation of a pati…
251G00000X	Community Based Hospice Care Agency	Agencies · Hospice Care, Community Based
2085R0205X	Radiological Physics Physician	A radiological physicist deals with the diagnostic and therapeutic applications of roentgen rays, gamma rays from sealed sources, ultrasonic radiation…
344800000X	Air Carrier	An air company that the Federal Aviation Administration, the certificate-holding district office (CHDO), regional Flight Standards Division (RFSD) off…
225XE0001X	Environmental Modification Occupational Therapist	Occupational therapy practitioners are experts at identifying the cause of difficulties in performance of activities of daily living and instrumental …

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 80171: Gabapentin Quantitative Assay, Serum or Plasma

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OpenPayer

CPT 80171: Gabapentin Quantitative Assay, Serum or Plasma

Sign up for cpt 80171 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 80171: Gabapentin Quantitative Assay, Serum or Plasma

Sign up for cpt 80171 policy alerts

CPT 80171: Gabapentin Quantitative Assay, Serum or Plasma

Sign up for cpt 80171 policy alerts

Clinical & Coding Specifications

Clinical Context

Related CPT Codes

Related Modifiers

Related Provider Taxonomies

Related Codes

What does CPT code 80171 represent?

In what clinical scenarios is gabapentin quantitative measurement used according to the page?

What specimen collection or related CPT codes are commonly associated with 80171?

Which payers are listed as covered in the summary metadata for this code?

What diagnoses are provided as clinically relevant for ordering code 80171?

References

Clinical & Coding Specifications

Clinical Context

Related CPT Codes

Related Modifiers

Related Provider Taxonomies

Related Codes

What does CPT code 80171 represent?

In what clinical scenarios is gabapentin quantitative measurement used according to the page?

What specimen collection or related CPT codes are commonly associated with 80171?

Which payers are listed as covered in the summary metadata for this code?

What diagnoses are provided as clinically relevant for ordering code 80171?

References