P-tau181 | P-tau181 | P-tau181 | P-tau217 | P-tau231 | P-tau231 | ||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Assay characteristics | |||||||||||||
Assay | Provider | Eli Lilly | ADx NeuroSciences | Quanterix | Eli Lilly | ADx NeuroSciences | Gothenburg (NA) | ||||||
Status | Prototype | Prototype | Commercial | Prototype | Prototype | Prototype | |||||||
Catalogue number | N/A | N/A | 103714 | N/A | N/A | N/A | |||||||
Biofluid | EDTA plasma | EDTA plasma | EDTA plasma | EDTA plasma | EDTA plasma | EDTA Plasma /Serum | |||||||
Platform | Simoa | Simoa HD-X | Simoa HD-X | Simoa HD-X | Simoa HD-X | Simoa HD-X | Simoa HD-x/HD-1 | ||||||
Antibodies | Name capture | AT270 | ADx252 | AT270 | FAb2 of IBA493 | ADx253 | ADx253 | ||||||
Epitope capture (AA) according to tau 441 numbering | Sequence 176-PPAPKT(p)P-182 phosphorylated specifically at threonine-181 | Phospho-Thr 181 and no cross-reactivity with phospho-Thr175 | Sequence 176-PPAPKT(p)P-182 phosphorylated specifically at threonine-181 | Peptide phosphorylated at Thr217 | Phosphorylated tau at T231 | Phosphorylated tau at T231 | |||||||
Name detector | LRL | ADx204 | Tau12 | 4G10E2 | ADx204 | Tau12 | |||||||
Epitope detector (AA) | 111–130 according to the Tau441 sequence | N-terminal, that recognizes all forms of tau except those phosphorylated at Tyr 18 | N-terminal epitope 6-QEFEVMEDHAGT-18 | 111–130 according to the Tau441 sequence | N-terminal, that recognizes all forms of tau except those phosphorylated at Tyr 18 | N-terminal epitope 6-QEFEVMEDHAGT-18 | |||||||
Assay protocol | Steps | 2-step assay | 2-step assay | 2-step assay | 3-step assay | 2-step assay | 3-step assay | ||||||
Incubation times, min | 60-5 | 60-10.5 | 35-5 | 30-5.15-5.15 | 60-5.15 | 40-7-7 | |||||||
Sample/calibrator volume, μL | 100 | 135 | 100 | 100 | 100 | 100 | |||||||
Beads volume, μL | 25 | 25 | 25 | 25 | 25 | 25 | |||||||
Detector volume, μL | 20 | 20 | 20 | 100 | 20 | 100 | |||||||
SBG volume, μL | 100 | 100 | 100 | 100 | 100 | 100 | |||||||
Assay reagents | Helper beads, % of beads | 66% | 50% | 60% | 50% | 50% | 0% | ||||||
SBG, pM | 150 pM | 50pM | 150 pM | 150 pM | 50 pM | 300 | |||||||
Detector, μg/mL | 1 | 0.6 | Unknown | 0.1 | 0.6 | 2 | |||||||
Calibrator | Type | Synthetic peptide | Synthetic peptide | Recombinant protein | Synthetic peptide | Synthetic peptide | Recombinant protein | ||||||
No. of calibrator points | 9 | 8 | 7 | 8 | 8 | 8 | |||||||
Range, pg/mL | 0.226-52 | 0.625-50 | 0.177-86 | 0.04-180 | 0.3125-40 | 0-64 | |||||||
Curve fit | 1/y2-weighted 5PL | 1/y2-weighted 5PL | 1/y2-weighted 4PL | 1/y2-weighted 4PL | 1/y2-weighted 5PL | 1/y2-weighted 4PL | |||||||
Sample dilution | Fold-dilution | 4 | 5 | 4 | 2 | 5 | 2 | ||||||
Recommended method | Automated | Manual | Automated | Automated | Manual | Automated | |||||||
Assay sensitivity and precision results | |||||||||||||
Sensitivity | Analytical LLOQ, pg/mL | 1.55 | 2.36 | 0.24 | 0.15 | 0.56 | 3.95 | ||||||
Functional LLOQ, pg/mL | 6.2 | 11.8 | 0.96 | 0.3 | 2.8 | 7.9 | |||||||
Concentrations of QC and KC panels | QC1: high, pg/mL | 15 | 26.8 | 3.8 | 2 | 7.4 | 26.7 | ||||||
QC2: intermediate, pg/mL | 6.9 | 13.3 | 1.3 | 0.6 | 4.7 | 17.1 | |||||||
QC3: low, pg/mL | 5.9 | 9.6 | 1.1 | 0.2 | 2.6 | 8.3 | |||||||
KC1, pg/mL | 4.05 | 9.75 | 3.22 | 0.64 | 1.41 | NA | |||||||
KC2, pg/mL | 16.69 | 17.87 | 70.35 | 1.99 | 5.72 | NA | |||||||
KC3, pg/mL | 142.01 | N/A | N/A | 61.6 | N/A | NA | |||||||
Precision QCs | Average Intra-assay %CV | 6.6 | 14.5 | 7.7 | 13.5 | 16.8 | 3.7 | ||||||
Average Inter-assay %CV | 10 | 15.2 | 19.5 | 14.1 | 27.7 | 5.1 | |||||||
Precision KCs | Average Intra-assay %CV | 5.6 | 16 | 6 | 9 | 19.9 | NA | ||||||
Average Inter-assay %CV | 9 | 23 | 29.5 | 10.5 | 30.5 | NA | |||||||
Clinical samples measurements | Number | 80 | 80 | 80 | 80 | 80 | 80 | ||||||
Range concentration, pg/mL | 2.69–21.65 | 1.91–77.29 | 0.89–8.65 | 0.04–1.93 | 1–16.07 | 5.68–25.8 | |||||||
Within calibrator range, % | 100% | 100% | 100% | 100% | 100% | 100% | |||||||
Range, CV% | 0.00–23.23 | 0.33–69.08 | 0.1–15.91 | 0.07–64 | 0.05–51.34 | 0.01–14.49 | |||||||
Average CV% | 5.74 | 12.20 | 5.83 | 14.20 | 8.25 | 3.35 | |||||||
n measured <LLOQ | 21 | 14 | 1 | 39 | 1 | 7 | |||||||
n measured > 20%CV | 1 | 13 | 0 | 16 | 3 | 0 | |||||||
Other validation results | |||||||||||||
Parallelism | Average slope of samples | 0.67 | 0.43 | 0.49 | 0.59 | 0.61 | 0.90 | ||||||
Range of slopes of samples | 0.55–0.75 | 0.33–0.61 | 0.39–0.61 | 0.53–0.68 | 0.48–0.72 | 0.85–0.97 | |||||||
Average slope of calibrator | 0.67 | 0.39 | 0.52 | 0.60 | 0.72 | 0.78 | |||||||
Parallelism, % | 99.6 | 110.3 | 94.6 | 98.7 | 84 | 116 | |||||||
Dilution linearity | Spiked concentration, pg/ml | 150 | 150 | 150 | 11 | 150 | |||||||
Df (x) | Mean %L | Df (x) | Mean %L | Df (x) | Mean %L | Df (x) | Mean %L | Df (x) | Mean %L | Df (x) | Df (x) | ||
Linear dilution factor with mean %Linearity | 1 | - | 1 | - | 1 | - | 1.00 | - | 1 | - | 1 | 1 | |
5 | 173 | 5 | 54 | 5 | 200 | 2.80 | 118 | 5 | 147 | 5 | 5 | ||
25 | 132 | 25 | 139 | 25 | 117 | 7.84 | 125 | 25 | 81 | 25 | 25 | ||
125 | 120 | 125 | 117 | 125 | 118 | 21.95 | 115 | 125 | 112 | 125 | 125 | ||
625 | 294 | 625 | 376 | 625 | 153 | 61.47 | 109 | 625 | 150 | 625 | 625 | ||
3125 | 426 | 3125 | 541 | 3125 | 265 | 172.10 | 134 | 3125 | 196 | 3125 | 3125 | ||
Recovery | Spike | Mean %R | Spike | Mean %R | Spike | Mean %R | Spike | Mean %R | Spike | Mean %R | Spike | Mean %R | |
Spiked concentration (pg/mL) With mean %Recovery | 0.8 | 102 | 0.85 | 54 | 0.8 | 72 | 0.4 | 108 | 0.85 | 131 | 1 | 150 | |
4.0 | 95 | 4.27 | 67 | 4.0 | 82 | 1 | 107 | 4.27 | 139 | 6 | 124 | ||
20.0 | 149 | 21.33 | 67 | 20.0 | 83 | 4 | 113 | 21.33 | 147 | 24 | 113 |