1. 2017 Update on the Alzheimer’s Association
Quality Control (QC) program
for CSF biomarkers
Kaj Blennow, Gothenburg University, Sweden

2. 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)

3. 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

4. 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)

5. 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

6. 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

7. 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

8. 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

9. CSF Aβ42 on the fully automated Lumipulse instruments
Lumipulse G 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

10. 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

11. 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

12. 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

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

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

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

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

17. 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

18. Thanks for listening !