Summary & Overview
CPT 0035U: RT–QuIC Prion Detection in Cerebrospinal Fluid
CPT code 0035U identifies a proprietary laboratory test: real–time quaking–induced conversion (RT–QuIC) for detection of abnormal prion proteins in cerebrospinal fluid. This PLA code is specific to the National Prion Disease Pathology Surveillance Center and reports a qualitative result to aid diagnosis of prion disease. Nationally, the code represents a highly specialized diagnostic service used in suspected prion disease cases where conventional assays are insufficient.
Key payers covered in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. The discussion examines payer coverage patterns, typical clinical contexts for test ordering, and how reporting a PLA code differs from more widely used laboratory codes.
Readers will learn the clinical purpose of the assay, typical site-of-service expectations, and the implications of the code being a PLA (provider- or manufacturer-specific) for billing and claims reporting. The publication also outlines policy-relevant considerations for payers and providers, including how a single-source PLA code can affect claim adjudication and documentation expectations. Data not available in the input for associated taxonomies, ICD-10 mappings, and related procedure codes are noted where applicable.
Billing Code Overview
CPT code 0035U is a Proprietary Laboratory Analyses (PLA) code for real–time quaking–induced conversion (RT–QuIC) for prion detection performed by the National Prion Disease Pathology Surveillance Center. The test detects abnormal prion proteins in cerebrospinal fluid (CSF) and yields a qualitative result (positive or negative) to aid in the diagnosis of prion disease.
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Service type: Specialized laboratory diagnostic testing using RT–QuIC methodology
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Typical site of service: Reference or specialized clinical laboratory (laboratory testing on CSF specimens)
Data not available in the input for modifiers, associated taxonomies, ICD-10 diagnoses, related codes, and service line.
Clinical & Coding Specifications
Clinical Context
A 62-year-old patient presents to a neurology clinic with rapidly progressive dementia, new-onset myoclonus, and cerebellar dysfunction over several weeks. The neurologist obtains neuroimaging and standard laboratory testing that are inconclusive for infectious, metabolic, or autoimmune causes. Cerebrospinal fluid (CSF) is obtained by lumbar puncture in the hospital or outpatient infusion/ambulatory surgery center and sent to the National Prion Disease Pathology Surveillance Center for specialized testing. The laboratory performs real–time quaking–induced conversion (RT–QuIC) on the CSF sample and returns a qualitative result (positive or negative) to aid in the diagnosis of prion disease. Typical workflow steps include CSF collection with appropriate labeling and chain-of-custody, shipping to the reference center under required conditions, receipt and processing by the reference lab, performance of RT–QuIC, and reporting of the qualitative result to the ordering clinician for integration with clinical, radiologic, and electroencephalographic findings.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
26 | Professional component | Use when reporting only the professional interpretation component if separate technical and professional components apply and are billed separately. |
| 52 | Reduced services | Use when the laboratory procedure is partially reduced or not fully performed for clinical reasons.