2017 Update on the Alzheimer’s Association Quality Control (QC) program for CSF biomarkers Kaj Blennow, Gothenburg University, Sweden

Background for starting the Alzheimer’s Association CSF program Large variability for CSF Aβ42 across laboratories Need of standardization efforts Variability due to: Pre-analytical factors e.g. type of test tube, CSF transfer, freeze-thaw effects, Analytical factors e.g. analytical procedures, technician training, run acceptance Assay manufacturing e.g. reagent purity, plate coating variability, calibrator stability, lot-to-lot consistency (batch bridging procedure)

The Alzheimer’s Association QC program for CSF biomarkers • Ongoing project since 2009 • Led by Gothenburg University, funded by the Alzheimer’s Association (private sponsor) Principle for the QC program: For each round, 3 QC samples (pooled CSF) are sent out 2 unique samples - for comparisons between labs 1 identical sample - for comparisons over time Frequency: 3 times per year > 90 labs Goals for the QC program Assess analytical and assay variability (NOT pre-analytical factors) monitor accuracy of CSF biomarker measurements for clinical laboratories  identify skewed results with the aim for harmonization of levels between labs monitor longitudinal drift in CSF biomarker levels in clinical clinical laboratories  monitor assay performance and batch-to-batch variation for assays  stimulate kit vendors to produce high quality assays

Laboratories n the Alzheimer’s Association QC program The QC program started in 2009  24 rounds completed Increasing number of laboratories participating Increasing number of assay formats in the program, but some (IBL) with few users (so far)

Assays in the Alzheimer’s Association QC program – Aβ42 • Innotest Aβ1-42 ELISA (Innogenetics) / Fujirebio Since Round 1 (2009) Aβ1-42, T-tau, P-tau RTU (ready-to-use) calibrator version Since Round 15 (2014) • Alzbio3 xMAP (Innogenetics) / Fujirebio Since Round 1 (2009) Aβ1-42, T-tau, P-tau Luminex • MSD ECL MesoScale Since Round 1 (2009) Aβ42, Aβ40, Aβ38 V-Plex (validated assays) Since Round 12 (2013) • Euroimmune ELISA ADx / Euroimmune Since Round 16 (2014) Aβ1-42, Aβ1-40, T-tau • Elecsys Aβ1-42 ECL-Cobas Roche Diagnostics Since Round 16 (2014) Fully automated • Lumipulse Aβ1-42 ECL Fujirebio Since Round 21 (2016) Fully automated

The CSF biomarker assays on fully automated clinical analyzers • Fully automated - minimize variations due to differences in laboratory procedures - reduced between-run, between-batch and between-lab variations Single sample analysis  fast results (< 30 min) to the clinician Roche Diagnostics – Cobas Fujirebio - Lumipulse

standardized to the mass spectrometry RMP for CSF Aβ42 (r= 0.93) MP03 vs. P02 r = 0.998 MP03 vs. P03 r = 0.996 P02 vs. P03 r = 0.997 Minimal variations between lots of reagents

The Cobas Elecsys fully automated assay - first round in the Alzheimer’s Association QC program Innotest ELISA Cobas Elecsys  fully automated instruments give a marked reduction in between-lab variability

CSF Aβ42 on the fully automated Lumipulse instruments Lumipulse G1200 Lumipulse G600 II (benchtop model) Analytical performance (in-house data) CSF Aβ42  CVs of 2-5% within-run, between instrument and between-day IFCC-WG CSF Commutability study III 37 individual CSFs 3 candidate Aβ1-42 CRMs (low, medium, high) Analyzed for Aβ1-42 by Lumipulse G1200 and the SRM mass spec Certified Reference Method r= 0.98 The Lumipulse assay is standardized to the mass spectrometry RMP Aβ42

The Lumpulse fully automated assay - first round in the Alzheimer’s Association QC program Round 21 – 2016 8 different results for Lumipulse Aβ1-42 on QC samples 21A and 21B 2 results from different lots of reagents  fully automated instruments give a marked reduction in between-lab variability

Report format in the QC program – unique samples Results in relation to mean and individual values for other labs Deviation from group mean over time

Report format in the QC program – longitudinal sample Results in relation to mean and individual values for other labs Deviation in absolute value over time

Monitoring between-batch variability in the QC program Example from Round 24 – 2017 Innotest ELISAs No evident batch-to-batch differences

The Alzheimer’s Association QC program – results 2016 - 2017 CSF Aβ42

The Alzheimer’s Association QC program – results 2016 - 2017 CSF Aβ40

CSF Phospho tau (P-tau) The Alzheimer’s Association QC program – results 2016 - 2017 CSF Total tau (T-tau) CSF Phospho tau (P-tau)

The Alzheimer’s Association QC program – summary of status The QC program will:  Continue to monitor the performance of the AD CSF biomarker assays - between lab CVs - longitudinal differences between batches of reagents  Continue to serve as an aid to individual labs - monitoring accuracy of measurements - monitoring longitudinal drift in measurements - basis for accreditation of AD CSF biomarker assays

Thanks for listening !