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CPT 0548U: Glial Fibrillary Acidic Protein (GFAP) Plasma Test

CPT code 0548U designates a Proprietary Laboratory Analyses (PLA) test for Glial Fibrillary Acidic Protein (GFAP) measured in plasma using a chemiluminescent enzyme immunoassay. This manufacturer-specific code applies only to the GFAP test from Neurocode USA Inc. and Fujirebio Diagnostics Inc. and signals a targeted diagnostic tool for assessing GFAP levels in clinical settings. Nationally, PLA codes like 0548U matter because they identify unique assays with specific clinical indications and billing pathways, influencing laboratory reporting, payer coverage decisions, and clinical adoption.

Key payers discussed include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. The publication provides an overview of payer coverage patterns, where available benchmarks are summarized, and any notable policy or coding guidance that affects billing for manufacturer-specific laboratory tests. Clinical context covers the test’s role as a plasma biomarker measuring GFAP via chemiluminescent enzyme immunoassay and typical laboratory settings where it is performed.

Readers will learn how CPT code 0548U is defined, which payers are relevant to national coverage considerations, and what types of benchmarks and policy updates to expect for PLA-designated laboratory tests. Data not available in the input will be noted explicitly in corresponding sections.

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Billing Code Overview

CPT code 0548U is a Proprietary Laboratory Analyses (PLA) code for the Glial Fibrillary Acidic Protein (GFAP) Blood Test produced by Neurocode USA Inc. and Fujirebio Diagnostics Inc. The code applies exclusively to a single, manufacturer-specific plasma assay that measures GFAP levels using a chemiluminescent enzyme immunoassay technique.

Service type: Proprietary laboratory diagnostic test (PLA)

Typical site of service: Clinical laboratory or hospital laboratory

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CPT 0548U: Glial Fibrillary Acidic Protein (GFAP) Plasma Test

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Get alerted when payer policies referencing 0548U are released or updated.

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Billing Code Overview

Service type: Proprietary laboratory diagnostic test (PLA)

Typical site of service: Clinical laboratory or hospital laboratory

Clinical & Coding Specifications

Clinical Context

A middle-aged patient presents to the emergency department after a head trauma caused by a fall from standing height. The patient is conscious but reports worsening headache and intermittent confusion. The emergency clinician orders a panel of blood biomarkers, including a Glial Fibrillary Acidic Protein (GFAP) plasma assay (0548U) manufactured/performed by Neurocode USA Inc. or Fujirebio Diagnostics Inc., to help identify potential intracranial injury and assist in triage decisions. Blood is drawn in the ED, processed per the laboratory's chemiluminescent enzyme immunoassay protocol, and results are reported to the treating clinician within the laboratory turnaround time. Findings are integrated with clinical exam and head CT results to guide disposition: discharge with observation, neurosurgical consultation, or hospital admission for further monitoring.

Coding Specifications

Modifier	Description	When to Use
`00`	No modifier (default)	Use when no special circumstances apply and the service is reported normally.
`22`	Increased procedural services	Use when work or resources required to perform the laboratory analysis are substantially greater than typical (document justification).
`52`	Reduced services	Use when the test is partially reduced or incomplete but still performed and reported (document reason).
`53`	Discontinued procedure	Use when the specimen collection or testing was started but discontinued for medical or technical reasons; report per payer policy.
`59`	Distinct procedural service	Use when a separate, distinct laboratory test or service is performed the same day and needs to be reported separately.
`90`	Reference (outside) laboratory	Use when the specimen was sent to an outside/reference laboratory for testing and the billing entity is reporting the test performed elsewhere.
`91`	Repeat clinical diagnostic laboratory test	Use when the same GFAP assay is repeated on the same day for verification or monitoring purposes.
`QW`	CLIA waived test	Use if the specific assay were CLIA-waived (not typical for PLA high-complexity assays) — apply only if applicable per lab certification.
`XE`	Separate encounter	Use when the laboratory service represents a different encounter from other services on the same day (specific to NCCI modifier set).

Taxonomy Code	Specialty	Notes
207Q00000X	Neurology	Neurologists order and interpret GFAP testing in traumatic or neurodegenerative contexts.
207L00000X	Emergency Medicine	Emergency physicians commonly order GFAP in acute head injury triage.
208000000X	Pathology & Laboratory Medicine	Laboratory directors and clinical pathologists oversee assay performance and result validation.
207R00000X	Neurosurgery	Neurosurgeons use GFAP results when assessing need for operative intervention or monitoring.
163W00000X	Clinical Neurophysiology	Specialists may use biomarker data alongside other neurodiagnostic testing for diagnostic correlation.

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`S06.0X0A`	Concussion without loss of consciousness, initial encounter	GFAP testing can aid in identifying neuronal or glial injury in concussive head trauma and help triage need for imaging and observation.
`S06.2X0A`	Diffuse traumatic brain injury without loss of consciousness, initial encounter	GFAP levels may correlate with diffuse brain injury severity and assist clinical assessment.
`S06.3X0A`	Focal brain injury without loss of consciousness, initial encounter	Used when focal intracranial injury is suspected; GFAP may support diagnosis alongside imaging.
`S06.4X0A`	Epidural hemorrhage without loss of consciousness, initial encounter	Elevated GFAP can indicate intracranial hemorrhage presence and severity in trauma.
`S06.5X0A`	Traumatic subdural hemorrhage without loss of consciousness, initial encounter	GFAP assists in detecting traumatic intracranial bleeding and informs management decisions.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`71045`	Radiologic examination, chest; single view, frontal	May be ordered concurrently in trauma evaluations for concurrent thoracic injury assessment; not directly related to GFAP testing but part of multi-system trauma workup.
`70450`	CT scan, head or brain; without contrast	Commonly performed before or after GFAP testing in suspected intracranial injury to visualize hemorrhage or structural injury; GFAP can assist in triage for CT.
`81002`	Urinalysis, non-automated, without microscopy	Frequently performed as part of ED panel during initial trauma evaluation; ancillary to biomarker testing.
`80053`	Comprehensive metabolic panel	Often ordered alongside biomarker testing to assess baseline metabolic status and guide management.
`99000`	Handling and/or conveyance of specimen for transfer from the physician's office to a laboratory	Used when specimens for `0548U` are collected in one location and transported to the performing lab; documents specimen handling logistics.

CPT 0001U: PreciseType HEA Multiplex Erythrocyte Antigen Assay

CPT-0002U-POLYPDX-URINE-METABOLOMIC-ASSAY-ADENOMATOUS-POLYP-RISK

CPT 0002U: Urine Metabolomic Polyp Risk Assay (PolypDX™)

CPT-0003U-OVAR-A-NEXT-GENERATION-OVARIAN-CANCER-RISK-ASSAY

CPT 0003U: Overa™ (OVA1 Next Generation) Ovarian Cancer Risk Assay

CPT-0005U-PROSTATE-EXOSOMEDX-INTELLISCORE-GENE-EXPRESSION-URINE-TEST

CPT 0005U: ExosomeDx Prostate (IntelliScore) Urine Gene Expression Risk Test

CPT-0007U-TOXPROTECT-URINE-DRUG-SCREEN-WITH-DNA-AUTHENTICATION

CPT 0007U: ToxProtect Urine Drug Screen with DNA Authentication

CPT-0008U-H-PYLORI-ANTIBIOTIC-RESISTANCE-SEQUENCING-PANEL

CPT 0008U: H. pylori Antibiotic Resistance Panel, Gene Sequence Analysis

CPT-0009U-DEPARRAY-HER2-FISH-TUMOR-CELL-ISOLATION

CPT 0009U: DEPArray HER2 Tumor‑Cell Isolation with FISH Analysis

CPT-0010U-BACTERIAL-TYPING-WHOLE-GENOME-SEQUENCING-MAYO-CLINIC

CPT 0010U: Bacterial Typing by Whole Genome Sequencing, Mayo Clinic

CPT-0011U-CORDANT-CORE-ALGORITHMIC-ORAL-FLUID-DRUG-TEST

CPT 0011U: Cordant CORE™ Oral Fluid Drug Test with Algorithmic Steady‑State Comparison

CPT-0016U-BCR-ABL1-MAJOR-MINOR-FUSION-TRANSCRIPT-TESTING

CPT 0016U: BCR–ABL1 Major and Minor Breakpoint Fusion Transcript Testing

Showing 1–10 of 536

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

Coding Specifications

Modifier	Description	When to Use
`00`	No modifier (default)	Use when no special circumstances apply and the service is reported normally.
`22`	Increased procedural services	Use when work or resources required to perform the laboratory analysis are substantially greater than typical (document justification).
`52`	Reduced services	Use when the test is partially reduced or incomplete but still performed and reported (document reason).
`53`	Discontinued procedure	Use when the specimen collection or testing was started but discontinued for medical or technical reasons; report per payer policy.
`59`	Distinct procedural service	Use when a separate, distinct laboratory test or service is performed the same day and needs to be reported separately.
`90`	Reference (outside) laboratory	Use when the specimen was sent to an outside/reference laboratory for testing and the billing entity is reporting the test performed elsewhere.
`91`	Repeat clinical diagnostic laboratory test	Use when the same GFAP assay is repeated on the same day for verification or monitoring purposes.
`QW`	CLIA waived test	Use if the specific assay were CLIA-waived (not typical for PLA high-complexity assays) — apply only if applicable per lab certification.
`XE`	Separate encounter	Use when the laboratory service represents a different encounter from other services on the same day (specific to NCCI modifier set).

Taxonomy Code	Specialty	Notes
207Q00000X	Neurology	Neurologists order and interpret GFAP testing in traumatic or neurodegenerative contexts.
207L00000X	Emergency Medicine	Emergency physicians commonly order GFAP in acute head injury triage.
208000000X	Pathology & Laboratory Medicine	Laboratory directors and clinical pathologists oversee assay performance and result validation.
207R00000X	Neurosurgery	Neurosurgeons use GFAP results when assessing need for operative intervention or monitoring.
163W00000X	Clinical Neurophysiology	Specialists may use biomarker data alongside other neurodiagnostic testing for diagnostic correlation.

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`S06.0X0A`	Concussion without loss of consciousness, initial encounter	GFAP testing can aid in identifying neuronal or glial injury in concussive head trauma and help triage need for imaging and observation.
`S06.2X0A`	Diffuse traumatic brain injury without loss of consciousness, initial encounter	GFAP levels may correlate with diffuse brain injury severity and assist clinical assessment.
`S06.3X0A`	Focal brain injury without loss of consciousness, initial encounter	Used when focal intracranial injury is suspected; GFAP may support diagnosis alongside imaging.
`S06.4X0A`	Epidural hemorrhage without loss of consciousness, initial encounter	Elevated GFAP can indicate intracranial hemorrhage presence and severity in trauma.
`S06.5X0A`	Traumatic subdural hemorrhage without loss of consciousness, initial encounter	GFAP assists in detecting traumatic intracranial bleeding and informs management decisions.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`71045`	Radiologic examination, chest; single view, frontal	May be ordered concurrently in trauma evaluations for concurrent thoracic injury assessment; not directly related to GFAP testing but part of multi-system trauma workup.
`70450`	CT scan, head or brain; without contrast	Commonly performed before or after GFAP testing in suspected intracranial injury to visualize hemorrhage or structural injury; GFAP can assist in triage for CT.
`81002`	Urinalysis, non-automated, without microscopy	Frequently performed as part of ED panel during initial trauma evaluation; ancillary to biomarker testing.
`80053`	Comprehensive metabolic panel	Often ordered alongside biomarker testing to assess baseline metabolic status and guide management.
`99000`	Handling and/or conveyance of specimen for transfer from the physician's office to a laboratory	Used when specimens for `0548U` are collected in one location and transported to the performing lab; documents specimen handling logistics.

CPT 0001U: PreciseType HEA Multiplex Erythrocyte Antigen Assay

CPT-0002U-POLYPDX-URINE-METABOLOMIC-ASSAY-ADENOMATOUS-POLYP-RISK

CPT 0002U: Urine Metabolomic Polyp Risk Assay (PolypDX™)

CPT-0003U-OVAR-A-NEXT-GENERATION-OVARIAN-CANCER-RISK-ASSAY

CPT 0003U: Overa™ (OVA1 Next Generation) Ovarian Cancer Risk Assay

CPT-0005U-PROSTATE-EXOSOMEDX-INTELLISCORE-GENE-EXPRESSION-URINE-TEST

CPT 0005U: ExosomeDx Prostate (IntelliScore) Urine Gene Expression Risk Test

CPT-0007U-TOXPROTECT-URINE-DRUG-SCREEN-WITH-DNA-AUTHENTICATION

CPT 0007U: ToxProtect Urine Drug Screen with DNA Authentication

CPT-0008U-H-PYLORI-ANTIBIOTIC-RESISTANCE-SEQUENCING-PANEL

CPT 0008U: H. pylori Antibiotic Resistance Panel, Gene Sequence Analysis

CPT-0009U-DEPARRAY-HER2-FISH-TUMOR-CELL-ISOLATION

CPT 0009U: DEPArray HER2 Tumor‑Cell Isolation with FISH Analysis

CPT-0010U-BACTERIAL-TYPING-WHOLE-GENOME-SEQUENCING-MAYO-CLINIC

CPT 0010U: Bacterial Typing by Whole Genome Sequencing, Mayo Clinic

CPT-0011U-CORDANT-CORE-ALGORITHMIC-ORAL-FLUID-DRUG-TEST

CPT 0011U: Cordant CORE™ Oral Fluid Drug Test with Algorithmic Steady‑State Comparison

CPT-0016U-BCR-ABL1-MAJOR-MINOR-FUSION-TRANSCRIPT-TESTING

CPT 0016U: BCR–ABL1 Major and Minor Breakpoint Fusion Transcript Testing

Showing 1–10 of 536

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 0548U: Glial Fibrillary Acidic Protein (GFAP) Plasma Test

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Billing Code Overview

OpenPayer

CPT 0548U: Glial Fibrillary Acidic Protein (GFAP) Plasma Test

Sign up for cpt 0548U policy alerts

Billing Code Overview

Clinical & Coding Specifications

Clinical Context

Coding Specifications

Related Diagnoses

Related CPT Codes

Related Codes

References

Clinical & Coding Specifications

Clinical Context

Coding Specifications

Related Diagnoses

Related CPT Codes

Related Codes

References