Zwolle, Netherlands
Zwolle, Netherlands

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Weykamp C.,Queen Beatrix Hospital | Weykamp C.,Location Queen Beatrix Hospital | John G.,Norwich University | Gillery P.,University Hospital of Reims | And 8 more authors.
Clinical Chemistry | Year: 2015

BACKGROUND: A major objective of the IFCC Task Force on Implementation of HbA1c Standardization is to develop a model to define quality targets for glycated hemoglobin (Hb A1c). METHODS: Two generic models, biological variation and sigma-metrics, are investigated. We selected variables in the models for Hb A1c and used data of external quality assurance/proficiency testing programs to evaluate the suitability of the models to set and evaluate quality targets within and between laboratories. RESULTS: In the biological variation model, 48% of individual laboratories and none of the 26 instrument groups met the minimum performance criterion. In the sigmametrics model, with a total allowable error (TAE) set at 5 mmol/mol (0.46% NGSP), 77% of the individual laboratories and 12 of 26 instrument groups met the 2σ criterion. CONCLUSIONS: The biological variation and sigma-metrics models were demonstrated to be suitable for setting and evaluating quality targets within and between laboratories. The sigma-metrics model is more flexible, as both the TAE and the risk of failure can be adjusted to the situation - for example, requirements related to diagnosis/monitoring or international authorities. With the aim of reaching (inter)national consensus on advice regarding quality targets for Hb A1c, the Task Force suggests the sigma-metrics model as the model of choice, with default values of 5 mmol/mol (0.46%) for TAE and risk levels of 2σ and 4σ for routine laboratories and laboratories performing clinical trials, respectively. These goals should serve as a starting point for discussion with international stakeholders in the field of diabetes. © 2015 American Association for Clinical Chemistry.


Drion I.,Diabetes Center | Cobbaert C.,Leiden University | Groenier K.H.,Diabetes Center | Groenier K.H.,University of Groningen | And 7 more authors.
BMC Nephrology | Year: 2012

Background: Non-equivalence in serum creatinine (SCr) measurements across Dutch laboratories and the consequences hereof on chronic kidney disease (CKD) staging were examined. Methods. National data from the Dutch annual external quality organization of 2009 were used. 144 participating laboratories examined 11 pairs of commutable, value-assigned SCr specimens in the range 52-262 mol/L, using Jaffe or enzymatic techniques. Regression equations were created for each participating laboratory (by regressing values as measured by participating laboratories on the target values of the samples sent by the external quality organization); area under the curves were examined and used to rank laboratories. The 10th and 90th percentile regression equation were selected for each technique separately. To evaluate the impact of the variability in SCr measurements and its eventual clinical consequences in a real patient population, we used a cohort of 82424 patients aged 19-106 years. The SCr measurements of these 82424 patients were introduced in the 10 th and 90th percentile regression equations. The newly calculated SCr values were used to calculate an estimated glomerular filtration rate (eGFR) using the 4-variable Isotope Dilution Mass Spectrometry traceable Modification of Diet in Renal Disease formula. Differences in CKD staging were examined, comparing the stratification outcomes for Jaffe and enzymatic SCr techniques. Results: Jaffe techniques overestimated SCr: 21%, 12%, 10% for SCr target values 52, 73 and 94 mol/L, respectively. For enzymatic assay these values were 0%, -1%, -2%, respectively. eGFR using the MDRD formula and SCr measured by Jaffe techniques, staged patients in a lower CKD category. Downgrading to a lower CKD stage occurred in 1-42%, 2-37% and 12-78.9% of patients for the 10th and 90th percentile laboratories respectively in CKD categories 45-60, 60-90 and >90 ml/min/1.73 m 2. Using enzymatic techniques, downgrading occurred only in 2-4% of patients. Conclusions: Enzymatic techniques lead to less variability in SCr measurements than Jaffe techniques, and therefore result in more accurate staging of CKD. Therefore the specific enzymatic techniques are preferably used in clinical practice in order to generate more reliable GFR estimates. © 2012 Drion et al.; licensee BioMed Central Ltd.


PubMed | World Health Organization, Ichikawa General Hospital, University of Nottingham, University Hospital of Reims and 5 more.
Type: Journal Article | Journal: Clinical chemistry | Year: 2015

A major objective of the IFCC Task Force on Implementation of HbA1c Standardization is to develop a model to define quality targets for glycated hemoglobin (Hb A1c).Two generic models, biological variation and sigma-metrics, are investigated. We selected variables in the models for Hb A1c and used data of external quality assurance/proficiency testing programs to evaluate the suitability of the models to set and evaluate quality targets within and between laboratories.In the biological variation model, 48% of individual laboratories and none of the 26 instrument groups met the minimum performance criterion. In the sigma-metrics model, with a total allowable error (TAE) set at 5 mmol/mol (0.46% NGSP), 77% of the individual laboratories and 12 of 26 instrument groups met the 2 criterion.The biological variation and sigma-metrics models were demonstrated to be suitable for setting and evaluating quality targets within and between laboratories. The sigma-metrics model is more flexible, as both the TAE and the risk of failure can be adjusted to the situation-for example, requirements related to diagnosis/monitoring or international authorities. With the aim of reaching (inter)national consensus on advice regarding quality targets for Hb A1c, the Task Force suggests the sigma-metrics model as the model of choice, with default values of 5 mmol/mol (0.46%) for TAE and risk levels of 2 and 4 for routine laboratories and laboratories performing clinical trials, respectively. These goals should serve as a starting point for discussion with international stakeholders in the field of diabetes.


John W.G.,Norwich University | Little R.,University of Missouri | Sacks D.B.,U.S. National Institutes of Health | Weykamp C.,Queen Beatrix Hospital | And 6 more authors.
Clinical Chemistry and Laboratory Medicine | Year: 2015

Background: The accurate and precise quantification of HbA1c is essential for the diagnosis and routine monitoring of patients with diabetes. We report an evaluation of the Trinity Biotech Premier Hb9210 analyser (Bray, Ireland/Kansas City, MO, USA), a boronate affinity chromatography-based high performance liquid chromatography (HPLC) system for the measurement of glycated haemoglobin. Methods: We evaluated the analytical performance of the Hb9210 as part of a multicentre evaluation. The effect of haemoglobin variants, other potential interferences and the performance in comparison to both the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) and National Glycohemoglobin Standardization Program (NGSP) reference systems, was assessed. Most of the centres participating also act as reference laboratories for both the IFCC standardisation network for HbA1c and the NGSP. Results: The combined data from all centres showed total coefficients of variation (CV) of 2.71%, 2.32% and 2.14% at low, medium and high values, respectively, for mmol/mol (SI units) and 1.62%, 1.59% and 1.68% for % (NGSP units), which are well below the recommended upper limits of 3% CV for mmol/mol (SI units) and 2% CV for % (NGSP). The analyser showed a good correlation to HbA1c methods currently used in clinical practice and the IFCC reference method procedure. Haemoglobin variants AC, AS, AE and AD do not affect the measurement of HbA1c. Overall the Hb9210 performs well across the whole analytical range. Conclusions: The Hb9210 performs well and is suitable for clinical application in the analysis of HbA1c. © 2015 by De Gruyter 2015.


Weykamp C.,Streekziekenhuis Koningin Beatrix | Lenters-Westra E.,European Reference Laboratory | Van Der Vuurst H.,Streekziekenhuis Koningin Beatrix | Slingerland R.,European Reference Laboratory | And 2 more authors.
Clinical Chemistry and Laboratory Medicine | Year: 2011

Background: We report an evaluation of the Menarini/ARKRAY ADAMS A1c HA-8180V analyser (HA-8180V), the fifth generation Menarini/ARKRAY ion-exchange HPLC for the measurement of HbA1c. Methods: We evaluated the analytical performance, the measurement of haemoglobin variants and the performance in comparison to major analytical methods. Results: Within-run, between-run and total CV were 0.2%, 0.4% and 0.7% at low HbA1c concentrations and 0.2%, 0.2% and 0.4% at high HbA1c concentrations, respectively. Trueness revealed a maximum deviation of 0.8 mmol/mol (IFCC units) or 0.1% (NGSP units) over the relevant analytical range. Linearity, carry-over and linear drift were excellent. Labile-HbA1c, carbamylated haemoglobin, icteric samples and variation in hematocrit did not affect HbA 1c outcome. Haemoglobin variants AS, AC and F do not affect HbA 1c outcome and are explicitly identified and correctly quantified. HbA1c can not be measured in samples with AE and AD, but these variants are identified correctly. In comparison to other methods used at present, the HA-8180V shows excellent performance. Conclusions: The HA-8180V performs at a high level and is fit for any clinical application. © 2011 by Walter de Gruyter Berlin New York.


PubMed | European Reference Laboratory
Type: Evaluation Studies | Journal: Clinical chemistry and laboratory medicine | Year: 2011

We report an evaluation of the Menarini/ARKRAY ADAMS A1c HA-8180V analyser (HA-8180V), the fifth generation Menarini/ARKRAY ion-exchange HPLC for the measurement of HbA(1c).We evaluated the analytical performance, the measurement of haemoglobin variants and the performance in comparison to major analytical methods.Within-run, between-run and total CV were 0.2%, 0.4% and 0.7% at low HbA(1c) concentrations and 0.2%, 0.2% and 0.4% at high HbA(1c) concentrations, respectively. Trueness revealed a maximum deviation of 0.8 mmol/mol (IFCC units) or 0.1% (NGSP units) over the relevant analytical range. Linearity, carry-over and linear drift were excellent. Labile-HbA(1c), carbamylated haemoglobin, icteric samples and variation in hematocrit did not affect HbA(1c) outcome. Haemoglobin variants AS, AC and F do not affect HbA(1c) outcome and are explicitly identified and correctly quantified. HbA(1c) can not be measured in samples with AE and AD, but these variants are identified correctly. In comparison to other methods used at present, the HA-8180V shows excellent performance.The HA-8180V performs at a high level and is fit for any clinical application.

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