Ordering Guidance

In individuals with a high clinical suspicion of Alzheimer disease, order ADEVL / Alzheimer Disease Evaluation, Spinal Fluid.

This test can only be performed on specimens collected and transported in polypropylene tubes. If this test is ordered and a polystyrene tube is received, it will be canceled and automatically reordered by the laboratory as CJDE / Creutzfeldt-Jakob Disease Evaluation, Spinal Fluid.

For cases where there is high suspicion of human prion disease supported by clinical or paraclinical magnetic resonance imaging features, order CJDE / Creutzfeldt-Jakob Disease Evaluation, Spinal Fluid.

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 this test.

Specimen Required

Supplies: CJD/RPD Evaluation Kit (T966)

Container/Tube:

Preferred: 2 Sarstedt CSF False Bottom Tubes 63.614.625 (2.5 mL)

Acceptable: Sarstedt 72.703.600 (1.5 mL) or Sarstedt 72.694.600 (2 mL)

Specimen Volume: 2 tubes; each containing 1.5 to 2.5 mL

Collection Instructions:

1. Perform lumbar puncture and discard the first 1 to 2 mL of cerebrospinal fluid (CSF).

2. Collect two tubes of CSF directly into an acceptable collection tube until the tube is at least 50% full.

3. Send CSF specimen in original collection tube. Do not aliquot.

Note: Polystyrene collection tubes are not acceptable. Exposure of CSF to polystyrene tubes may result in falsely low Abeta42 concentrations.

The Alzheimer's Association consensus protocol for handling of CSF for clinical measurements of Abeta42 and tau recommends using the drip method for CSF collection and directly collecting into a low-bind polypropylene tube. Although some clinicians prefer the syringe pull method due to speed of collection, the drip method reduces the risk of Abeta42 binding to the plastic of any syringe used.

4. Collection instructions can also be found on Spinal Fluid Specimen Collection Instructions for Creutzfeldt-Jakob Disease and Rapidly Progressive Dementia Evaluations (T974).