Summary & Overview
CPT 0459U: Elecsys Total Tau/Abeta42 Ratio, CSF ECLIA
CPT code 0459U designates a Proprietary Laboratory Analyses (PLA) assay for the Elecsys® Total Tau CSF (tTau) and β–Amyloid (1–42) CSF II (Abeta 42) Ratio from Roche Diagnostics. The test uses cerebrospinal fluid and an electrochemiluminescent immunoassay (ECLIA) to produce a tTau/Abeta42 ratio that can inform evaluation of patients with cognitive impairment. As a PLA code, 0459U applies to a single manufacturer-specific test and carries implications for coding specificity, billing clarity, and payer coverage determinations nationally.
Key payers discussed include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise national overview of clinical context, common sites of service, and the coding scope for this manufacturer‑specific CSF biomarker assay. The publication outlines payer relevance and typical contractual considerations for PLA codes, summarizes expected use cases in cognitive impairment assessment, and highlights where Data not available in the input limits further detail. This brief provides clinicians, laboratory directors, and billing professionals with the essential facts about CPT code 0459U, its clinical purpose, and the national payer landscape to inform administrative and clinical workflows.
Billing Code Overview
CPT code 0459U is a Proprietary Laboratory Analyses (PLA) code for the Elecsys® Total Tau CSF (tTau) and β–Amyloid (1–42) CSF II (Abeta 42) Ratio produced by Roche Diagnostics Operations Inc. The test uses cerebrospinal fluid and an electrochemiluminescent immunoassay (ECLIA) method to generate a tTau/Abeta42 ratio value that may assist clinicians in evaluating patients with signs of cognitive impairment.
Service type: Laboratory test — cerebrospinal fluid (CSF) immunoassay
Typical site of service: Clinical laboratory or hospital/inpatient outpatient laboratory service where CSF specimens are processed
Data not available in the input.
Clinical & Coding Specifications
Clinical Context
A 68-year-old patient presents to a neurology clinic with progressive memory loss and cognitive decline over 18 months. The neurologist documents objective cognitive impairment on bedside testing and orders cerebrospinal fluid (CSF) biomarker testing to aid in differential diagnosis between Alzheimer disease and other causes of dementia. A lumbar puncture is performed in the outpatient clinic or hospital setting by a neurologist or interventionalist to obtain CSF. The CSF specimen is sent to the laboratory for the proprietary Elecsys® Total Tau CSF (tTau) and β–Amyloid (1–42) CSF II (Abeta42) Ratio assay (report with CPT code 0459U). The laboratory performs an electrochemiluminescent immunoassay (ECLIA) and returns a tTau/Abeta42 ratio to the ordering clinician. The result is used as adjunctive information with clinical assessment, neuroimaging, and neuropsychological testing to support diagnosis and care planning.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
00 | No modifier — default | Use when no specific modifier applies to the laboratory service |
26 | Professional component | Use when reporting only the professional interpretation component if separated from the technical laboratory component |
52 | Reduced services | Use when the laboratory test is partially reduced in scope, quantity, or component |
53 | Discontinued procedure | Use if the specimen collection or testing was started but discontinued for documented clinical reasons |
62 | Two surgeons | Rare for lab testing; apply when two qualified providers share responsibility for an invasive procedure related to CSF collection when billing is partitioned |
76 | Repeat procedure by same provider (Note: not in provided list) | Data not available in the input. |
78 | Unplanned return to OR by same physician (listed) | Use if an invasive CSF-related procedure required return to the operating room for complication management (billing the related procedural service) |
80 | Assistant surgeon | Use when an assistant surgeon is documented for the invasive CSF collection procedure (applies to the procedural code, not to the lab PLA) |
82 | Assistant surgeon (when qualified resident unavailable) | Use when an assistant surgeon is necessary and a qualified resident is unavailable for the CSF collection procedure |
AS | Physician assistant, nurse practitioner, or clinical nurse specialist services for assistant at surgery | Use when an advanced practice clinician served as surgical assistant for CSF collection-related procedure |
TC | Technical component | Use when reporting only the laboratory technical component (instrumentation, reagent, analytic processing) for 0459U if the payer allows split billing |
QK | Medical direction of two, three, or four concurrent anesthesia procedures by a physician (listed) | Not typically applicable to lab testing; retained for completeness when anesthesia is billed for lumbar puncture under monitored anesthesia care |
QX | Modifier for assistant surgeon — CRNA (listed) | Use when a CRNA provided services related to anesthesia for an invasive CSF collection procedure |
QY | Medical direction of one CRNA by an anesthesiologist (listed) | Use when applicable to anesthesia services for CSF collection |
| Taxonomy Code | Specialty | Notes |
|---|---|---|
2084P0800X | Neurology | Neurologists commonly order CSF biomarker testing for cognitive disorders |
207L00000X | Pathology & Laboratory Medicine | Laboratory specialists and pathologists oversee processing and interpretation of CSF biomarker assays |
207P00000X | Clinical Laboratory | Clinical laboratory personnel perform the ECLIA testing and result reporting |
208VP0002X | Neuropsychiatry | Neuropsychiatrists may order CSF biomarker testing as part of dementia evaluation |
2083N0402X | Geriatric Medicine | Geriatricians commonly manage older adults with cognitive impairment and order CSF biomarkers |
Related Diagnoses
| ICD-10 Code | Description | Clinical Relevance |
|---|---|---|
G30.9 | Alzheimer disease, unspecified | Common indication for CSF tTau/Abeta42 ratio testing to support diagnosis |
F02.80 | Dementia in other diseases classified elsewhere without behavioral disturbance | Used when dementia is attributed to another primary disease and CSF biomarkers assist evaluation |
F03.90 | Unspecified dementia, unspecified | Applied when cognitive decline is documented and CSF biomarkers are used in workup |
R41.3 | Other amnesia | Used when memory loss prompts biomarker testing to clarify etiology |
G31.84 | Mild cognitive impairment, so stated | CSF biomarker testing may be ordered in MCI to assess risk of progression to Alzheimer disease |
Related CPT Codes
| CPT Code | Description | Relationship to This Procedure |
|---|---|---|
62270 | Spinal puncture, lumbar, diagnostic | Performed to obtain CSF specimen prior to laboratory testing with 0459U |
36415 | Collection of venous blood by venipuncture | May be performed concurrently for comparative serum testing or ancillary labs during the same visit |
83520 | Drug assay, qualitative, multiple drug classes; chromatographic method | Example of additional laboratory analyses sometimes ordered alongside CSF biomarker testing for differential diagnosis or toxicology |
88360 | Immunohistochemistry or immunocytochemistry, per single antibody stain | Not directly for CSF but represents specialized laboratory immunoassay techniques; related conceptually to biomarker assays |
96372 | Therapeutic, prophylactic, or diagnostic injection (specify substance or drug); subcutaneous or intramuscular | May be used when intrathecal therapeutics are administered during the same episode of care (billing related procedural services) |