Pilots large scale 2006 (36) 2007 (46) 2008 (55) 2009 (59)

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1 QA-LSD Quality Assessment Enzyme Analysis for Lysosomal Storage Diseases Pilots large scale 26 (36) 27 (46) 28 (55) 29 (59) 21

2 QA-pilots for LSD s What is it all about? Constant supply of material A constant difficulty for QA-schemes Detecting enzyme deficiencies Material form LSD patients: EBV lymphoblasts Reproducibility Duplicate, triplicate or quadruplicate samples

3 QA-pilots for LSD s The 28 and 29 pilots Participants pilot 28 : 55 participants (Protein- & 4MU-standards) pilot 29-1: 59 participants (Leuko s, EBV lympho s) pilot 29-2: 27 participant (DBS) 6 samples & 8 enzymes, LSD patients included Result have been presented at the ESGLD Workshop 29 September 1-13, 29, Bad Honnef A paper on 4 years large scale QA-LSD (to be published in 21) Authors from ESGLD, SKML and ERNDIM

4 Protein- and 4MU-standards, 4 duplicates (QA-ESGLD/ERNDIM 28) Unintended, EBV cell cultures were lost by fungus infection Confusing I did not double-check the samples Informative The identical samples emphasised the problem of reconstitution of lyophilised samples

5 Protein- and 4MU-standards, 4 duplicates (QA-ESGLD/ERNDIM 28) Best performers: 21 of 47 labs Protein: CV s of 4 duplicates < 2% 4MU: R 2 >.98 7 Results of QA-ESGLD/ERNDIM-28 Protein data participant UEQB Results of QA-ESGLD/ERNDIM-28 4MU data participant UEQB y = x R 2 =.9999 Experimental value (mg/vial) Experimental value (nmol/vial) Reference value (mg/vial) Reference value (nmol/vial)

6 Protein- and 4MU-standards, 4 duplicates (QA-ESGLD/ERNDIM 28) Can be improved: 26 of 47 labs Protein:CV of 1 or more duplicates > 2% 4MU: R 2 <.98 Experimental value (mg/vial) Results of QA-ESGLD/ERNDIM-28 Protein data participant HQ Results of QA-ESGLD/ERNDIM-28 4MU data participant HQ y =.7331x R 2 =.25 Experimental value (nmol/vial) Reference value (mg/vial) Reference value (nmol/vial)

7 Reproducibility of protein/vial 29 duplicate samples leukocytes Lab No CV Protein Labs 59 participants no data 16 labs CV > 28% 2%<CV < 28% CV < 2% 2 labs 6 labs 35 labs

8 16 14 Reproducibility of 11 enzymes and protein duplicate leukocyte samples 29 8 CV (%) no data CV > 2% CV < 2% Laboratory No. 15 labs 38 labs 6 labs New labs 62

9 Proficiency testing enzyme analysis in EBV lympho s α-glucosidase alpha-glu (% mean of mean control) control) % β-hexosaminadase beta-hex-a (% A mean (% of control) mean control) 2 Tay-Sachs patient infantile-pompe patient

10 Proficiency testing enzyme analysis in EBV lympho s 29 β-glucosidase BGLU (% of mean control) Gaucher I patient

11 Proficiency testing enzyme analysis in EBV lympho s 29 Arylsulphatase A ASA (% of mean control) % Clear ASA deficiency % (3 of 25) 37% (7 of 19) MLD assay at 37 ASA 37C ASA C MLD assay at Arylsulphatase A (% of mean control)

12 1 Why was ASA deficiency missed? Rotterdam uses pncs assay in 96 well plates 75 Marijke Boer: precipitate in the wells EBV lympho s ASA Arylsulphatase A activity 5 With precipitate No precipitate Control (n=8) MLD (n=2) 34; 35 ( 57%) 8.6; 5.5 ( 11%) EBV lympho s Arylsulphatase A (% of mean control) ASA 37C ASA C MLD assay at

13 Feedback from Participants about ASA assay Which SOP is used by best-performers? Question: Which SOP is used by best performers? Asked to the 9 best-performers Response: 1 of 9 participants

14 Dried Blood Spots First QA-DBS 29 (QA-ESGLD/ERNDIM 29-2) Eight 3-mm punches per mm blood spot 6 μl blood / mm spot

15 QA-DBS 29 (QA-ESGLD/ERNDIM 29-2) 27 participants 6 samples / lab 2 spots ( mm) / sample 8 enzymes. Chitotriosidase α-galactosidase β-galactosidase α-glucosidase β-glucosidase β-hexosaminidase A β-hexosaminidase (A+B) α-iduronidase Number of laboratories compliance of data entry 1 41 % Non-responders Number of enzymes investigated

16 Coefficients of Variation enzyme analysis in DBS (n=3) 1 8 enzymes C V (%) Laboratory #

17 Proficiency testing enzyme analysis in DBS (QA-ESGLD/ERNDIM 29-2) 9 % Proficiency testing for GSD II on DBS 113% 6 % 2 Fabry Pompe 1 Pompe 2 α Galactosidase AGAL activity act. (% mean (% control) mean control) GAA activity % of mean of control α Glucosidase act. (% mean control) Pompe 1 Pompe 2

18 Dried Blood Spots Blood samples for DBS How to prevent wasting patients blood?

19 Cost break up: QA for LSD s Cost estimate (5 participants) 1 enzymes: 8 conventional samples + DBS / year EBV lympho s from LSD patients, 6 samples 75 Control leukocytes, 2 samples (Rottedam) DBS samples (All participants) Preparation of 8 homogenates (Rotterdam) 5 Freeze-drying, Shipping & Data Base managing 15 Transport of EBV cells & miscellaneous 25 Costs of ERNDIM 1 Total cost / participant 4

20 QA for LSD s, a new ERNDIM scheme Starting 21 Participants pay the costs Lyophilised homogenates of leuko s & EBV-lympho s from LSD-patients. DBS samples included, when available Website adaptations for Enzyme analysis Error free extraction of raw-data from the ERNDIM database Graphical presentation (dot-plots) Patient samples expressed as % of normal enzyme activity Certificate of Participations

21 QA for LSD s, a new ERNDIM scheme What needs to be done Some thoughts about the Certificate of Participation: score for detecting LSD patients (+) score for reproducibility (+ to ) score for detecting enzyme deficiencies in normal samples ( ) score No show on an ERNDIM DPT meeting ( ) Poor performance should have consequences Repetitive poor-performance should have severe consequences We should ask our accrediting bodies to set more stringent rules Merely participating is not sufficient, the scores should get moer weight. Otto van Diggelen, ERNDIM Meeting Basel 29

22 Enduring QA-programme for the LSD s