Freeze

This documentation pertains to the May 2025 Freeze of the plasma Quanterix HD-X/Simoa ALZpath pTau217- Madison dataset.

Origin

These plasma assay results come from the University of Wisconsin ADRC Biomarker Lab and were analyzed using the Simoa pTau217 v2 (ALZpath) assay on the Quanterix HD-X platform.

Sample Selection

Samples are collected on an ongoing basis, starting August 3, 2011. Samples were stored in varying tube types depending on the study and date of collection.
For detailed information, refer to the WRAP and/or ADRC pre-analytic protocols for CSF and plasma collection, available on the Wisconsin Alzheimer's Program KnowledgeBase.

Sample and Participant Characteristics

This dataset includes 6310 observations on 2051 participants (543 ADRC; 1507 WRAP; 1384 female; 380 URG; 121 MCI and 23 Dementia at first visit; 112 MCI and 41 Dementia at last visit; 9 participant(s) are aged 90+, of those not: mean first and last ages of 62.4 and 67.5, respectively; mean first and last days since baseline of 2191 and 4067, respectively).

Per data sharing agreements with the Oneida nation, data from Native American participants are not included in this dataset. 

Analytes

• Phosphorylated tau 217

Dynamic Range

• 0.00732 - 30.0 pg/mL (with 3x dilution)

All the concentrations reported for this analyte are in pg/mL.

Methods

On December 16, 2023, the HD-X instrument was replaced. A crosswalk analysis was performed to assess correlation with the previous instrument (Serial No. 2710020402). Crosswalks were also conducted at each kit lot change using a consistent set of N = 35 EDTA plasma samples. Correlations were evaluated using the Pearson correlation coefficient, and linear regression was applied to standardize results to lot #999008. This information is included in the current dataset in the standardization column.

Code Availability

The entire processing pipeline is available on the SMPH GitLab. For any questions, please contact Ramiro Rea Reyes(rreareyes@medicine.wisc.edu).

Funding/Acknowledgments

Papers including data obtained from these assays should acknowledge NIH R01 AG027161 (the Wisconsin Registry for Alzheimer's Prevention) and/or NIH P30 AG062715 (the Wisconsin Alzheimer's Disease Research Center).

A manuscript is currently under development under the guidance of Sterling Johnson and Henrik Zetterberg. This work focuses on: Validation of plasma pTau217 against amyloid and tau PET imaging; Longitudinal characterization of pTau217; Associations with cognitive outcomes.

For further details or collaboration inquiries, please contact Rachael Wilson or Ramiro Rea Reyes.

See Also

Biofluids Data Documentation

Document History