Synonyms
- 217
- p-Tau217
- pTau217
- Tau
Special Instructions
This test is not approved for use in New York state.
Expected Turnaround Time
5 - 7 days
Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.
Related Documents
Specimen Requirements
Specimen
Plasma, frozen
Volume
1 mL
Minimum Volume
0.75 mL (Note: This volume does not allow for repeat testing.)
Container
Lavender-top (EDTA) tube
Collection
Draw blood in lavender-top (EDTA) tube. Invert to mix with preservatives. Centrifuge and transfer plasma to a labeled plastic transport tube and freeze.
Storage Instructions
Freeze.
Stability Requirements
Temperature | Period |
|---|---|
Frozen | -20°C: 14 days -80°C: 2 months |
Freeze/thaw cycles | Stable x3 |
Causes for Rejection
Serum specimen; improper labeling; grossly hemolyzed
Test Details
Use
This test is used to aid in the biological identification of Alzheimer's disease by measuring phosphorylated tau 217, which has been shown in the literature to be a surrogate of amyloid pathology. Additionally, pTau-217 can be used for monitoring patients on newly approved anti-amyloid therapy.
Clinical cutoff value was established using samples from a well-established patient cohort characterized with amyloid PET data. A pTau-217 value of >0.18 is a reported surrogate marker for beta amyloid pathology and can be used to facilitate biological identification of Alzheimer's disease.1 pTau-217 has also been used in clinical trials to monitor patients on anti-amyloid therapy.2,3
Limitations
This test is performed by Fujirebio Lumipulse chemiluminescent enzyme immunoassay (CLEIA). Values obtained with different methods cannot be used interchangeably. The validated limit of quantification is 0.06 pg/mL. Assay detection limit is 0.03 pg/mL.
This test was developed and its performance characteristics determined by Labcorp. It has not been cleared or approved by the Food and Drug Administration.
Methodology
Fujirebio Lumipulse chemiluminescent enzyme immunoassay (CLEIA)
Reference Interval
0.00–0.18 pg/mL
Footnotes
1. Ashton NJ, Brum WS, Molfetta GD, et al. Diagnostic Accuracy of a Plasma Phosphorylated Tau 217 Immunoassay for Alzheimer Disease Pathology. JAMA Neurol. 2024 Mar 1;81(3):255-263.38252443
2. Ashton NJ, Janelidze S, Mattsson-Carlgren N, et al. Differential roles of Aβ42/40, p-tau231 and p-tau217 for Alzheimer's trial selection and disease monitoring. Nat Med. 2022 Dec;28(12):2555-2562.36456833
3. Pontecorvo MJ, Lu M, Burnham SC, et al. Association of Donanemab Treatment With Exploratory Plasma Biomarkers in Early Symptomatic Alzheimer Disease: A Secondary Analysis of the TRAILBLAZER-ALZ Randomized Clinical Trial. JAMA Neurol. 2022 Dec 1;79(12):1250-1259.36251300
LOINC® Map
| Order Code | Order Code Name | Order Loinc | Result Code | Result Code Name | UofM | Result LOINC |
|---|---|---|---|---|---|---|
| 484390 | p-tau217 | 484391 | p-tau217 | pg/mL | Pending | |
| 484390 | p-tau217 | 484392 | Footnotes | N/A |
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