Test Overview
Alzheimer’s disease (AD) is a neurodegenerative disorder hallmarked by extracellular amyloid-beta (AB) plaques and intracellular neurofibrillary tangles of hyperphosphorylated tau (p-tau), which lead to progressive loss of neuronal function and cell death. These pathologies can be present and developing in the brain for years before any symptoms become apparent. During this buildup there are several specific proteins that are released into the cerebrospinal fluid (CSF) that have been identified as reliable biomarkers for the diagnosis of AD.
Tau protein normally acts to stabilize the axons of neurons, but when it is hyperphosphorylated (p-tau) it becomes prone to aggregating into neurofibrillary tangles, leading to neuronal dysfunction and death. There are several variants of p-tau that have been identified as significant in AD, differentiated by the location of the phosphorylation site.
p-Tau 217 has been identified as a particularly noteworthy isoform. Levels of p-Tau 217 in both CSF and blood have been shown to be elevated in AD and increase over the course of the disease, indicating it could be a valuable tool for diagnosis.
Plasma p-Tau 217 levels correlate well with amyloid and tau PET imaging and perform as well as tests using CSF. This ALZpath p-Tau 217 assay was highly accurate in identifying amyloid-PET positive patients (AUC=.932).
| Test Code: | p-Tau 217 |
| Synonyms: | ALZpath p-Tau 217, plasma p-Tau 217, ALZpathDx |
| Methodology: | In-house single-molecule assay (Powered by Simoa®) |
| Validation: | Laboratory Developed Test (LDT) |
| Reference Range: | ≤0.63 pg/mL |
Performance
| Frequency: | EDTA plasma |
| Expected Turnaround: | 3 - 10 days |
| Sample Report: | Coming Soon |
Our offices are only able to receive samples Mon-Fri, so samples must be shipped Mon-Thur. Samples arriving over the weekend may need to be redrawn.
Specimen
| Specimen Type: | EDTA Plasma |
| Container: | Lavender-top EDTA tube |
| Preferred Volume: | 1 mL |
| Minimum Volume: | 0.5 mL |
| Rejection Criteria: | Grossly hemolytic, lipemic, or icteric. If the sample arrives at room temperature. |
| Collection and Processing: | No patient preparation is required for sample collection. Draw blood in tube(s) with EDTA activator. Centrifuge tubes at 1800 - 2200 x g for 10-15 minutes. Draw off plasma (top layer) into aliquot tubes with pipette, ensuring not to take RBCs (middle/bottom layers). Store aliquot tubes in refrigerator (2° C - 8° C) until shipping. |
| Specimen Handling: | Transport refrigerated or frozen |
| Specimen Stability: | 7 days at room temperature (15⁰ C – 25⁰ C) Up to 5 freeze / thaw cycles |
Additional Information
- This is a laboratory developed test, its performance was determined by Neurocode USA Inc. It has not been cleared or approved by the Food and Drug Administration.
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