Summary & Overview
CPT 80184: Phenobarbital Quantitative Assay
CPT code 80184 represents a technical laboratory test that quantifies phenobarbital, an anticonvulsant medication. This code is used when a lab analyst performs the assay to determine phenobarbital concentration in a patient specimen for therapeutic drug monitoring, toxicity assessment, or medication management. As a commonly ordered toxicology and therapeutic drug test, CPT code 80184 matters nationally for clinicians managing seizure disorders and for laboratories that support medication monitoring programs.
Key payers discussed include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of clinical context for phenobarbital testing, typical sites of service, and the role this assay plays in patient care. The publication also outlines billing and coding considerations, common modifiers used with laboratory services (listed in the metadata), and where to find additional guidance. Data not available in the input is noted where applicable.
This summary offers clinicians, laboratory managers, and billing professionals a focused primer on the clinical purpose of CPT code 80184 and what to expect when this test is ordered and billed on a national level.
Billing Code Overview
CPT code 80184 describes a laboratory quantitative analysis of phenobarbital in a patient specimen. The service reflects the technical laboratory testing performed by a lab analyst to measure the concentration of the anticonvulsant medication phenobarbital.
Service type: Clinical laboratory drug quantitation
Typical site of service: Clinical laboratory or hospital laboratory (inpatient or outpatient specimen collection and processing)
Clinical & Coding Specifications
Clinical Context
A 28-year-old patient with a history of generalized tonic-clonic seizures presents for routine therapeutic drug monitoring. The patient is prescribed phenobarbital and reports variable adherence and recent breakthrough seizures. A blood specimen is collected at an outpatient laboratory draw station and sent to the hospital clinical chemistry/toxicology laboratory. The lab analyst performs a quantitative assay to determine serum phenobarbital concentration (CPT 80184) to assess therapeutic level, toxicity risk, and medication adherence.
Typical workflow: a clinician orders a serum phenobarbital level with an ICD-10 diagnosis supporting anticonvulsant monitoring; the phlebotomist obtains the specimen; the specimen is accessioned and routed to the clinical chemistry or toxicology section; a medical laboratory scientist or technician runs the quantitative assay (immunoassay or chromatographic method) and verifies analytic quality control; results are reviewed and released to the ordering provider; the clinician interprets results for dose adjustment or further testing.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
26 | Professional component | When billing only the physician interpretation or professional portion if separate from the technical lab work. |