Freeze

This documentation pertains to the May 2025 Freeze of the plasma Auger MSD/Biotechne ProteinSimple pTau217, NfL, GFAP - Madison dataset.

Origin

These plasma assays were run at the University of Wisconsin-Madison's Institute on Aging-MIDUS Biocore Lab using two platforms, Meso Scale Discovery (MSD) and Biotechne ProteinSimple.

Sample Selection

Samples were collected between July 2012 and June 2023. Samples were stored in 0.5mL Sarstedt tubes at -80 degrees Celsius.
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 90 observations on 89 participants (28 ADRC; 61 WRAP; 53 female; 7 URG; 13 MCI and 1 Dementia at first visit; 13 MCI and 1 Dementia at last visit; 0 participant(s) are aged 90+, of those not: mean first and last ages of 69.4 and 69.4, respectively; mean first and last days since baseline of 4028 and 4032, respectively).

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

Analytes

• Phosphorylated tau 217 (pTau217; fg/mL)
• Neurofilament light (NfL; pg/mL)
• Glial fibrillary acidic protein (GFAP; pg/mL)

Dynamic Range

• pTau217: 880-3,590,000 fg/mL
• NfL: 2.7-10,290 pg/mL (72x1 Cartridge)
• GFAP: 2.52-9,600 pg/mL (72x1 Cartridge)

Methods

The MSD platform was initially utilized to calibrate other pTau217 assays. The current preferred platform is the Quanterix HD-X.

pTau217

• Platform: Meso Scale Discovery (MSD); Meso Scale Discovery, Rockville, MD, USA
• Instrument: SQ120
• Assay name: S-Plex Human Tau (pT217) cat #K151APFS, lot# K00S0173
• Testing Dates: April 2024
• Assay type: Electrochemiluminescent immunoassay-This ultrasensitive method of detection uses electrochemiluminescent labels, SULFO-tags, attached to detection antibodies that interact with the electrodes emitted from the instrument to quantify the concentration of analyte within the sample. Samples were run in duplicates.
• Sample Dilution Factor: 2-fold

*NfL and GFAP were quantified across two cartridges. One cartridge was designed to quantify a maximum of 72 samples per analyte. The remaining samples were multiplexed on a second cartridge which also included the quantification of CXCL10 and BLC.

NfL*

• Platform: Bio-Techne ProteinSimple
• Instrument: Ella (ProteinSimple)
• 1st Assay (72x1) format: Simple Plex Cartridge Kit Human NfL cat. # SPCKB-PS-002448, kitID: 342512, lot #: 35316, cartridge ID: 377063
• 2nd Assay (32x4) format: Simple Plex Cartridge Kit Human NfL, GFAP, BLC and CXCL10 cat. #SPCKC-PS010115, cartridge ID: 363876, kitID: 330106, lot #: 36931
• Testing Dates: July 2024
• Assay Type: Automated Sandwich ELISA-Samples were centrifuged at 1000g for 15 minutes and diluted 1:2 before being plated into their respective inlets on the cartridge. Then, wash buffer was added to all designated inlets. High and low controls were prepared by reconstitutions and dilutions using manufacturer's sample diluent (SD13), then plated. This method of detection uses automated microfluidic technology that quantifies natural and recombinant NfL using three glass nano reactors (GNR).
• Sample Dilution Factor: 2-fold

GFAP*

• Platform: Bio-Techne ProteinSimple
• Instrument: Ella (ProteinSimple)
• Testing Dates: July 2024
• 1st Assay (72x1) format: Simple Plex Cartridge Kit Human GFAP (2nd Gen) cat. #SPCKB-PS-009134, kitID: 340211, lot #: 35310, cartridge ID: 374564
• 2nd Assay (32x4) format: Simple Plex Cartridge Kit Human NfL, GFAP, BLC and CXCL10 cat. #SPCKC-PS010115, cartridge ID: 363876, kitID: 330106, lot #: 36931
• Assay Type: Automated Sandwich ELISA-Samples were centrifuged at 1000g for 15 minutes and diluted 1:2 before being plated into their respective inlets on the cartridge. Then, wash buffer was added to all designated inlets. High and low controls were prepared by reconstitutions and dilutions using manufacturer's sample diluent (SD13), then plated. This method of detection uses automated microfluidic technology that quantifies natural and recombinant GFAP using three glass nano reactors (GNR).
• Sample Dilution Factor: 2-fold

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).

See Also

Biofluids Data Documentation

Document History