Sterile vial/container

Freeze specimen (if possible at -80 °C) in a sterile container within 20 minutes of collection.

The sample should be frozen as soon as possible (within 2-3 hours of sample collection). If the sample is left un-frozen for a prolonged time (10-24 hours) a comment should be included on the request form. 

Sterile vial/container

Frozen (strict) - 28 days

If possible, freeze and store at -80 °C

Refrigerated - 14 days

Enzyme Immunoassay (EIA)

Abnormal Prion Protein:

This assay is a second-generation seeding aggregation assay known as a real-time quaking-induced conversion assay (RT-QuIC). Briefly, the cerebrospinal fluid (CSF) sample is mixed with reaction buffer that contains fluorescence emitting dye and truncated recombinant hamster prion proteins (amino acids 90-231) in a 96-well black microtiter plate with clear optical bottom. Each 96-well plate includes 2 positive controls and 2 negative controls plus 20 samples. Each sample is tested in 4 replicate wells. At completion of the reaction, if at least one of the reaction wells per sample is scored positive, testing is repeated for that sample. The assay is performed on a BMG Omega FLUOStar instrument.(Orru CD, Groveman BR, Hughson AG, et al. RT-QuIC assays for prion disease detection and diagnostics. Methods Mol Biol. 2017;1658:185-203)

Total Tau:

The Roche cobas assay for determining total Tau in CSF uses a sandwich-assay principle. Two biotinylated monoclonal Tau-specific antibodies and a monoclonal Tau-specific antibody labeled with a ruthenium complex react to form a sandwich complex. Streptavidin-coated microparticles are added, and the interaction between biotin and streptavidin allows the complex to become bound to the solid phase. The reaction mixture is then aspirated into the measuring cell, microparticles are captured onto the electrode, and the application of voltage induces chemiluminescent emission, which is measured by a photomultiplier.(Package insert: Elecsys Total-Tau CSF. Roche Diagnostics; V 2.0, 10/2023)

Phospho-Tau:

The Roche cobas assay for determining phospho-Tau in CSF uses a sandwich-assay principle. A biotinylated monoclonal antibody specific for phosphorylation at threonine 181 and a monoclonal Tau-specific antibody labeled with a ruthenium complex react to form a sandwich complex. Streptavidin-coated microparticles are added, and the interaction between biotin and streptavidin allows the complex to become bound to the solid phase. The reaction mixture is then aspirated into the measuring cell, microparticles are captured onto the electrode, and the application of voltage induces chemiluminescent emission, which is measured by a photomultiplier.(Package insert: Elecsys Phospho-Tau (181P) CSF. Roche Diagnostics; V 1.0, 12/2022)