Standardization of hemoglobin A 1c : myth or reality? Andrea Mosca

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1 Standardization of hemoglobin A 1c : myth or reality? Andrea Mosca Dept. Pathophysiology and Transplantation Centre for Traceability in Laboratory Medicine (CIRME) University of Milano, Milano (IT) contents IFCC approach to the standardization of HbA 1c - IFCC Network - Manufacturers -Customers Conclusions 2

2 contents IFCC approach to the standardization of HbA1c - IFCC Network - Manufacturers - Customers Conclusions 3 Electrofocusing of hemoglobins HbA3 HbA1c HbAo HbF Intmed methb HbS HbA2 courtesy Prof. J.O. Jeppson 4

3 Primary reference materials (IRMM 466 and 467) Secondary reference materials (blood panels) CRM AD500 (?) IFCC reference measurement procedure (HPLC-CE or HPLC-MS) IFCC Network Manufacturer s working calibrator Manufacturer s product calibrator Patient Sample Manufacturer s internal reference measurement procedure Manufacturer s standing measurement procedure Routine measurement procedure Manufacturer Individual laboratory Mosca et al, Clin Chem Lab Med 2007;45: HbA 1c is the stable adduct of glucose to the N-terminal valine of the β chain of hemoglobin Hexapeptide N-terminal Val β chains α chains 6

4 Flow chart for Reference Methods Hemolysate Enzymatic Cleavage HPLC-Capillary Capillary Electrophoresis HPLC-Mass Spectrometry Approved by IFCC Jeppsson et al, Clin Chem Lab Med 2002;40:78-89 Comparison between the IFCC reference method and three designated comparison methods 12,00 NGSP = 0,92xIFCC + 2,15 10,00 DSM 8,00 6,00 NGSP Mono-S JDS 4,00 Mono S = 0,989xIFCC ,00 JDS = 0,927xIFCC+1,73 0,00 0,00 2,00 4,00 6,00 8,00 10,00 12,00 % HbA1c IFCC method Hoelzel et al Clin Chem 2004;50:

5 Clin Chem 2004; 50:

6 Dϋsseldorf 2 Study Cape Town Study Berlin 2 Study California 2 Study

7 California Berlin Cape Town Dϋsseldorf HbA 1c, mmol/mol (approved) Melbourne Amsterdam Orlando Los Angeles HbA 1c, % (approved) contents IFCC approach to the standardization of HbA 1c - IFCC Network - Manufacturers -Customers Conclusions 14

8 Monitoring Programme Manufacturers 2009 CV in % 6.0% 4.0% 2.0% HPLC Immuno Affinity POCT IFCC-RM mmol/mol NGSP % Best Performance 15 Bias A. Mosca -UniMI 16

9 17 contents IFCC approach to the standardization of HbA 1c - IFCC Network - Manufacturers -Customers Conclusions 18

10 Analytical goals Braga et al, Clin Chim Acta 2011;411: Weykamp et al, Clin Chem 2011;57(8) 20

11 Essential steps for achieving the standardization of HbA 1c Mosca et al, Clin Chem Lab Med 2013, in press 21 Internal Quality Control Level 1 mean: 5.5 % CV = 1.6 % Bio-Rad Variant II, Dual Kit Lyphochek Diabetes Control Lot Level 2 mean: 9.6 % CV = 1.3 %

12 -20 C liofilo IQC CV = 2.4 % -20 C -80 C sangue CV = 2.6 % Cobas Integra Braga et al, Biochimica clinica 2010;34: IQC data from the manufacturers 24

13 EQAS fresh whole blood N = 220 labs 99 % within TE Lenters-Westra 25 et al, Diab Technol Therap 2011; 13: samples in duplicate (blind over one year), every 2 weeks EQAS lyophilized materials

14 EQAS lyophilized materials TE = 6.0 % 27 BC 2008

15 6.5 NGSP units, % int. rif DCCT 1993 SI units, mmol/mol

16 Why using IFCC standardized IFCC? Improved reliability and metrological traceability Abandoning tests with poor performance Measurement units aligned to the S.I. system Avoiding the complications of using two different measurement units (different reference intervals, different decisional limitis, different analytical goals) Simpler report Expanding the physiopathological range Greater attention to the result Better relationship to the physiopathological meaning Rohlfing et al, Diabetes Care 2002;25:275-8

17 Survey on HbA 1c Italy (1/2) (data from 237 laboratories, ) Survey on HbA 1c Italy (2/2) (data from 237 laboratories, )

18 Conclusions A complete reference system is available for HbA 1c Laboratory professionals have to carefully evaluate the methods (IFCC certificates), to calibrate them and to run periodical IQC and EQAS exercises EQAS results are difficult to be compared each other (matrix effect, target values, programmes, criteria) Manufacturers should help into developing more adequate control materials Scientific Societies should constantly stimulate and monitor the process 35 Standardization of hemoglobin A 1c : myth or reality? AND/OR 36

19 Aknowledgments RenataPaleari(University of Milano, Milano, IT) (HPLC analysis, data elaboration) Cas Weykamp (Qeen Beatrix H, Winterswijk, NL) (IFCC Network HbA 1c ) Patricia Kaiser, Hans Reinauer(INSTAND ev, Duesseldorf, DE) (ID-MS reference measurement procedure) 37