Home
HelpTest Code B181C Phosphorylated Tau 181, Cerebrospinal Fluid
Useful For
Quantitative measurement of phosphorylated Tau at threonine 181(pTau 181) in human cerebrospinal fluid
Method Name
Chemiluminescent Immunoassay
Reporting Name
Phospho-Tau 181, CSF
NY State Available
Yes
CLIA Laboratory Number
24D1040592
Aliases
p-Tau 181
Specimen Type
Cerebrospinal Fluid
Specimen Required
Container/Tube: Sarstedt Aliquot Tube, 5 mL 62.504.040
Specimen Volume: 1 mL
Collection Instructions:
1. Perform lumbar puncture and discard the first 1 to 2 mL of cerebrospinal fluid (CSF).
2. Collect CSF directly into one of the listed collection tubes
Note: Polypropylene collection tubes must be used. Polystyrene collection tubes are not acceptable.
3. Inspect specimen for visible blood contamination:
a. If bloody, centrifuge specimen and transfer supernatant to a new one of the listed collection tubes prior freezing and sending to laboratory. The supernatant, not the cellular material, is used for analysis.
b. If specimen is clear, centrifugation is not necessary.
4. Freeze sample upright prior to placing in transport container.
Reject Due To
|
Gross hemolysis |
Reject |
|
Thawing |
Cold OK; Warm reject |
|
Gross lipemia |
Reject |
|
Gross icterus |
Reject |
Specimen Stability Information
|
Specimen |
Temperature |
Time |
Special Container |
|
CSF |
Frozen |
90 days |
Clinical Information
Two neuropathologic features observed in the brain of patients with Alzheimer disease dementia are the presence of plaques composed of beta-amyloid (Abeta) peptides and intracellular neurofibrillary tangles containing hyperphosphorylated Tau (tubulin-associated unit) proteins (pTau). These 2 groups of molecules are the most established biomarkers of the disease used in clinical and research practice. Measuring of certain pTau (such as pTau181) proteins in cerebrospinal fluid may be used to assess the presence of amyloid pathology.
The p-Tau181 assay used here has been reported to have an area under the receiver operating characteristic curve of 0.84 (95%CI 0.75–0.93) for detection for an abnormal amyloid-positron emission tomography as assessed by visual read.(1)
Reference Values
≤ 63 pg/mL
Interpretation
A cutoff of 63 pg/mL has an 80% positive percent agreement, 83% negative percent agreement, and 81% overall percent agreement with amyloid-positron emission tomography (PET).(1)
A phosphorylated Tau181 concentration less than or equal to 63 pg/mL will be most consistent with a negative amyloid-PET.
A phosphorylated Tau181 concentration greater than 63 pg/mL will be most consistent with a positive amyloid-PET.
Cautions
Phosphorylated-Tau181 (pTau181) results must be interpreted in conjunction with other diagnostic tools, such as neurological examination, neurobehavioral tests, imaging, and routine laboratory tests.
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. Caution should be used in interpretation of results, and the laboratory should be alerted if the result does not correlate with the clinical presentation.
Results obtained with different assay methods or kits may be different and cannot be used interchangeably.
Clinical Reference
1. Alcolea D, Pegueroles J, Munoz L, et al. Agreement of amyloid PET and CSF biomarkers for Alzheimer's disease on Lumipulse. Ann Clin Transl Neurol. 2019;6(9):1815-1824
2. Leitao MJ, Silva-Spinola A, Santana I, et al. Clinical validation of the Lumipulse G cerebrospinal fluid assays for routine diagnosis of Alzheimer's disease. Alzheimers Res Ther. 2019;11(1):91. Published 2019 Nov 23. doi:10.1186/s13195-019-0550-8
3. Gobom J, Parnetti L, Rosa-Neto P, et al. Validation of the LUMIPULSE automated immunoassay for the measurement of core AD biomarkers in cerebrospinal fluid. Clin Chem Lab Med. 2021;60(2):207-219. Published 2021 Nov 15. doi:10.1515/cclm-2021-0651
4. Campbell MR, Ashrafzadeh-Kian S, Petersen RC, et al. P-tau/Abeta42 and Abeta42/40 ratios in CSF are equally predictive of amyloid PET status. Alzheimer's Dement. 2021;13:e12190
Method Description
The Lumipulse G pTau 181 is an assay system for the quantitative measurement of phosphorylated Tau (pTau) 181 in cerebrospinal fluid specimens based on chemiluminescent immunoassay technology by a specific two-step sandwich immunoassay method on the Lumipulse G System. The specimen and biotinylated antibody solution are both added to the antibody coated particle solution. The pTau 181 in the specimen specifically binds to anti-pTau 181 monoclonal mouse antibody on the particles and biotinylated mouse antibody. Biotinylated antibody-antigen immunocomplexes are formed. The particles are washed and rinsed to remove unbound materials. Alkaline phosphatase labeled streptavidin specifically binds to biotinylated immuno-complexes on the particles. The particles are washed and rinsed to remove unbound materials. Substrate solution is added and mixed with the particles. 3-(2'-Spiroadamantyl)-4-methoxy-4-(3"-phosphoryloxy)-phenyl-1,2-dioxetane (AMPPD) contained in the substrate solution is dephosphorylated by the catalysis of alkaline phosphatase indirectly conjugated to particles. Luminescence (at a maximum wavelength of 477 nm) is generated by the cleavage reaction of dephosphorylated AMPPD. The luminescent signal reflects the amount of pTau 181 present in the sample.(Package insert: Lumipulse G pTau 181. Fujirebio Inc; 03/2023)
PDF Report
No
Day(s) Performed
Tuesday
Report Available
1 to 9 days
Specimen Retention Time
90 days
Test Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.
CPT Code Information
83520
LOINC® INFORMATION
|
Mayo Test ID |
Reporting Name |
Orderable LOINC Value |
|
B181C |
Phospho-Tau 181, CSF |
No LOINC Needed |