Summary & Overview
CPT 0584U: RT–QuIC Prion Test, CSF (Mayo Clinic)
CPT code 0584U designates a proprietary laboratory test for RT–QuIC Prion analysis performed on cerebrospinal fluid (CSF) by the Mayo Clinic. As a PLA code, it represents a single, manufacturer- or lab-specific assay that provides a qualitative (positive/negative) result to support the diagnosis of prion disease. Nationally, PLA codes like 0584U are important because they identify unique diagnostics that may have limited availability but high clinical specificity for rare, high-consequence conditions.
Key payers analyzed include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of the code’s clinical purpose, typical service setting, and payer coverage context. The publication summarizes common modifiers associated with laboratory services, discusses clinical context for RT–QuIC testing in suspected prion disease, and outlines what is known about payer interactions and reimbursement patterns for proprietary assays when available. Where input data are not provided, the report notes that information is not available. This resource is intended to inform billing, coding, and policy staff, laboratory managers, and clinicians about the coding identity, clinical role, and payer landscape for CPT code 0584U at a national level.
Billing Code Overview
CPT code 0584U is a Proprietary Laboratory Analyses (PLA) code that applies to a single, manufacturer- or laboratory-specific test: RT–QuIC Prion, CSF, from Mayo Clinic. The test uses real-time quaking-induced conversion (RT–QuIC) to detect abnormal prion proteins in cerebrospinal fluid (CSF) and yields a qualitative result (positive or negative) to aid in the diagnosis of prion disease.
Service type: Specialized laboratory diagnostic test (proprietary PLA)
Typical site of service: Clinical laboratory or hospital laboratory, with specimen collection from cerebrospinal fluid (CSF) typically performed in an inpatient or outpatient setting where lumbar puncture is available.
Clinical & Coding Specifications
Clinical Context
A typical patient is an adult referred to a neurology service with rapidly progressive cognitive decline, myoclonus, ataxia, or other signs suspicious for a prion disorder such as Creutzfeldt–Jakob disease. The clinician obtains a detailed neurologic history and exam, orders neuroimaging (brain MRI with diffusion-weighted imaging) and routine CSF testing (cell count, protein, glucose, and infectious studies). When clinical suspicion for a prion disease remains, the neurologist or inpatient team performs a lumbar puncture to collect cerebrospinal fluid (CSF). A portion of the CSF specimen is sent to Mayo Clinic for the proprietary RT–QuIC Prion, CSF test reported under CPT 0584U. The laboratory performs real–time quaking–induced conversion to detect abnormal prion protein seeding activity and returns a qualitative result (positive or negative) to aid diagnostic decision-making. Typical site of service includes inpatient hospital settings, hospital outpatient clinics, and specialized neurology or tertiary care centers. Billing uses PLA code 0584U only when the Mayo Clinic RT–QuIC assay is performed; documentation should include indication, lumbar puncture procedure note, CSF collection details, and result interpretation in the medical record.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
00 | Default/No modifier | Use when no special reporting modifiers apply to the service. |
22 | Increased procedural services | Use when documentation supports substantially greater work or complexity in specimen collection, processing, or consultation beyond typical expectations. |
52 | Reduced services | Use when the test was partially completed or a limited version of the service was furnished. |
53 | Discontinued procedure | Use when the related lumbar puncture or specimen submission was started but discontinued and the test not completed due to patient factors. |
| Taxonomy Code | Specialty | Notes |
|---|---|---|
| 207RG0100X | Neurology | Neurologists commonly order and interpret results in suspected prion disease. |
| 2080P0207X | Neuropathology | Neuropathologists may be involved in diagnostic correlation and interpretation of CSF prion testing. |
| 208D00000X | Clinical Laboratory / Pathology | Clinical laboratory directors and pathologists manage test validation, reporting, and QA for specialized assays. |
| 363LP0808X | Emergency Medicine | Emergency physicians may initiate workup in acute presentations that lead to CSF testing. |
| 207M00000X | Internal Medicine | Hospitalists and internists frequently coordinate inpatient lumbar puncture and ordering of specialized CSF tests. |
Related Diagnoses
| ICD-10 Code | Description | Clinical Relevance |
|---|---|---|
A81.0 | Creutzfeldt-Jakob disease | Primary prion disease for which RT–QuIC CSF testing is directly diagnostic support. |
G31.9 | Degenerative disease of nervous system, unspecified | Used when a progressive neurodegenerative process is suspected but not yet classified; RT–QuIC may help clarify etiology. |
G93.9 | Disorder of brain, unspecified | Applied in undifferentiated encephalopathy where prion disease is in the differential diagnosis. |
R41.3 | Other amnesia | Cognitive decline and memory loss prompting workup including CSF RT–QuIC. |
R41.82 | Altered mental status, unspecified | Acute or subacute changes in consciousness that lead to CSF testing as part of diagnostic evaluation. |
M62.82 | Myoclonus | Myoclonus is a common clinical feature in prion disease and supports ordering RT–QuIC testing. |
G11.9 | Hereditary ataxia, unspecified | Ataxia can be a presenting sign; used where degenerative causes including prion disease are considered. |
Related CPT Codes
| CPT Code | Description | Relationship to This Procedure |
|---|---|---|
62270 | Spinal puncture, lumbar, diagnostic (including needle or catheter placement), single or multiple; with or without imaging guidance | Performed to obtain CSF specimen that is sent for RT–QuIC testing. |
87635 | Infectious agent detection by nucleic acid (DNA or RNA); multiple organisms, amplified probe technique (e.g., meningitis/encephalitis panel) | Often ordered alongside CSF testing to evaluate common infectious causes of encephalopathy before or concurrent with prion testing. |
89240 | Preparation and conveyance of specimen for transfer to another laboratory; urine/stool/fluid | Used when CSF specimen requires special packaging, processing, or transport to an external reference lab such as Mayo Clinic. |
88360 | Immunohistochemistry or immunocytochemistry, per specimen; initial single antibody stain | May be used for neuropathology correlation on tissue specimens when available in the diagnostic workup of suspected prion disease. |
99000 | Handling and/or conveyance of specimen for transfer from physician to another lab | Used when additional administrative handling or special courier arrangements are required for sending CSF to a reference laboratory. |