CSF Testing for Prion Markers

14-3-3γ (ELISA), Total TAU (ELISA) and RT-QuIC for Prion Proteins
CPT Code 86317 (14-3-3 & TAU), 0035U (RT-QuIC)
Ordering Recommendation

May aid in the diagnosis of prion disease. RT-QuIC identifies the disease-causing agent. Total TAU and 14-3-3γ are indirect markers of neurodegenerative diseases.
Assumes that the patient has a history of a rapid neurodegenerative condition and does not have several conditionsi that might compromise the test results.

Methodology Quantitative Enzyme-Linked Immunosorbent Assay (ELISA). 
Real-Time Quaking-Induced Conversion (RT-QuIC)ii.
Available STAT No. 
Analytic Timeiii 7 business days.
Submit With Order NPDPSC Test Request Form


Specimen Requirements
Patient preparation The patient must be 12 years of age or older.
Specimen Type Cerebrospinal Fluid (CSF) obtained by lumbar puncture.
Required Container Saestedt CSF False Bottom Tubes 63.614.625 (2.5 ml).
Specimen Preparation The first 2ml of CSF that flows from the tap should be discarded. Collect 2 ml of CSF (1 ml minimum), avoiding bloody tap. The sample must be immediately frozen, at least in a -20°C freezer.
Storage/Transport Temperature

Frozen. Shipping transport on dry ice.iv.

Please note: shipments are not received on weekends and/or holidays. Ship only Monday through Thursday (priority overnight).

Unacceptable Conditions Bloody and insufficient sample quantity. Samples that are colored or contain blood cannot be performed for RT-QuIC and 14-3-3 GAMMA.
Remarks Complete the required test request form linked above.
Stability Freeze CSF at -20°C immediately after collection. 


Specimen Reporting
Critical Results None.
Reference Range(s) RT-QuIC: Negative
Total TAU (ELISA): 0-1149 pg/mL
14-3-3 GAMMA (ELISA): <173 - 1999 AU/mL.
Likelihood of Prion Disease RT-QuIC Positive: >98%
RT-QuIC Negative & Total TAU <499<0.2%
RT-QuIC Negative & Total TAU 500-2499 = <1%



i. Conditions include but are not limited to, subarachnoid hemorrhage, various encephalitis, stroke with acute infarction, multi-infarct dementia with acute infarction, brain neoplasm, and paraenoplastic neurological disorders. These conditions may yield false-positive results.
ii. CSF RT-QuIC has a diagnostic sensitivity and specificity of 90.3% and 98.5%, respectively (Rhoads DD, Neurology 2020).

iii. Expected turnaround time (business days) for results, beginning when the center receives the specimen.
iv. A recent re-evaluation of the shipment conditions of CSF specimens showed that shipment at room temperature caused a decrease in the accuracy of RT-QuIC, 14-3-3 protein, and TAU protein assays when compared with the shipment of frozen CSF samples on dry ice.