Test Directory

• t-Tau/p-Tau
• CJD Eval Interp, CSF
• RT-QuIC Prion, CSF
• Phospho-Tau(181P)
• Total-Tau

Assessment of Creutzfeldt-Jakob disease or other human prion disease in patients with rapidly progressive dementia.

In cases where there is high suspicion of human prion disease supported by clinical or paraclinical (MRI imaging) features, this test should be ordered.

Specimen Type: CSF

Collection Container: BlueTop SARSTEDT (CJD/RPD Evaluation Collection Kit)

Desired Specimen Volume: 4.5 mL (2.5 mL per tube)

1. Collect CSF via lumbar puncture.
2. Discard the first 1 to 2 mL of cerebrospinal fluid (CSF).
3. Collect two tubes of CSF directly into the blue top Sarstedt tubes included in the CJD/RPD Evaluation Kit.

MCL Spinal Fluid Specimen Collection may be reviewed

1. Transport 4.5 mL of CSF in two blue top Sarstedt tubes (original collection container).
2. Do not aliquot. Analysis needs to be performed using collection tube provided with kit.

For 12 hours before specimen collection, patient should not take multivitamins or dietary supplements (eg, hair, skin, and nail supplements) containing biotin (vitamin B7).

Transport to the laboratory frozen.

• Gross hemolysis
• Gross lipemia
• Gross icterus
• Discolored CSF
• Polystyrene and glass collection tubes. Exposure of CSF to polystyrene or glass tubes may result in falsely low beta-amyloid concentrations.

See patient report.

These test results should be interpreted in the appropriate clinical context along with other clinical and paraclinical findings. Only through neuropathological assessment of brain tissue can a definitive diagnosis of sporadic prion disease be established.

Some molecular subtypes of prion protein have been reported to have lower detectability by real-time quaking-induced conversion (RT-QuIC) assays.

Even small quantities of blood in cerebrospinal fluid (CSF) can result in false-negative RT-QuIC results.

The presence of fluorescent substances may interfere with testing and prevent an accurate interpretation of the RT-QuIC assay.

Careful consideration of the differential diagnosis is advised when RT-QuIC test results are unexpectedly negative. Repeat testing with RT-QuIC may be warranted if there is high suspicion of prion disease. A small subset of initially negative cases by RT-QuIC may become positive as the disease progresses. However, a small proportion of patients with definitive prion disease may be persistently negative by RT-QuIC. False-negative RT-QuIC results are most often encountered in cases of genetic prion disease, such as fatal familial insomnia and Gerstmann-Straussler-Scheinker disease, and in atypical sporadic prion disease subtypes that have slower indolent disease progression.

In rare cases, some individuals can develop antibodies to mouse or other animal antibodies (often referred to as human anti-mouse antibodies [HAMA] or heterophile antibodies), which may cause interference in some immunoassays. The presence of antibodies to streptavidin or ruthenium can also rarely occur and may interfere in this assay. Caution should be used in interpretation of results, and the laboratory should be alerted if the result does not correlate with the clinical presentation.

Early in the disease course, or in atypical cases, the disease progression may be slower and include significant clinical overlap (dementia, rigidity, myoclonus) with other potential causes of rapidly progressive dementia, including Alzheimer disease. In the latter case, it would be more appropriate to order RPDE / Rapidly Progressive Dementia Evaluation, Spinal Fluid.

• Prion
• CJD
• Creutzfeldt Jakob Disease
• Transmissible spongiform encephalopathies
• RT-QuIC
• Real-time quaking-induced conversion
• TSE
• Fatal Insomnia
• Gerstmann-Straussler-Scheinker disease
• Variant CJD