scholarly journals IFCC Reference System for Measurement of Hemoglobin A1c in Human Blood and the National Standardization Schemes in the United States, Japan, and Sweden: A Method-Comparison Study

2004 ◽  
Vol 50 (1) ◽  
pp. 166-174 ◽  
Author(s):  
Wieland Hoelzel ◽  
Cas Weykamp ◽  
Jan-Olof Jeppsson ◽  
Kor Miedema ◽  
John R Barr ◽  
...  
Keyword(s):  
Reference System ◽  
Clinical Chemistry ◽  
Method Comparison ◽  
Reference Method ◽  
The United States ◽  
Reference Laboratory ◽  
Regression Equations ◽  
National Programs ◽  
Method Comparison Study ◽  
The Relationship

Abstract Background: The national programs for the harmonization of hemoglobin (Hb)A1c measurements in the US [National Glycohemoglobin Standardization Program (NGSP)], Japan [Japanese Diabetes Society (JDS)/Japanese Society of Clinical Chemistry (JSCC)], and Sweden are based on different designated comparison methods (DCMs). The future basis for international standardization will be the reference system developed by the IFCC Working Group on HbA1c Standardization. The aim of the present study was to determine the relationships between the IFCC Reference Method (RM) and the DCMs. Methods: Four method-comparison studies were performed in 2001–2003. In each study five to eight pooled blood samples were measured by 11 reference laboratories of the IFCC Network of Reference Laboratories, 9 Secondary Reference Laboratories of the NGSP, 3 reference laboratories of the JDS/JSCC program, and a Swedish reference laboratory. Regression equations were determined for the relationship between the IFCC RM and each of the DCMs. Results: Significant differences were observed between the HbA1c results of the IFCC RM and those of the DCMs. Significant differences were also demonstrated between the three DCMs. However, in all cases the relationship of the DCMs with the RM were linear. There were no statistically significant differences between the regression equations calculated for each of the four studies; therefore, the results could be combined. The relationship is described by the following regression equations: NGSP-HbA1c = 0.915(IFCC-HbA1c) + 2.15% (r2 = 0.998); JDS/JSCC-HbA1c = 0.927(IFCC-HbA1c) + 1.73% (r2 = 0.997); Swedish-HbA1c = 0.989(IFCC-HbA1c) + 0.88% (r2 = 0.996). Conclusion: There is a firm and reproducible link between the IFCC RM and DCM HbA1c values.

Comparison of the International Federation of Clinical Chemistry and Japan Diabetes Society reference methods for conversion to the National Glycohemoglobin Standardization Program values

2019 ◽  
Vol 56 (4) ◽  
pp. 508-514
Author(s):  
Katsuyuki Nakajima ◽  
Isao Koyama ◽  
Makoto Watanabe ◽  
Masakazu Nakamura ◽  
Yoshihiro Miyamoto ◽  
...  
Keyword(s):  
Clinical Chemistry ◽  
Method Comparison ◽  
Reference Method ◽  
International Federation ◽  
Haemoglobin A1c ◽  
Regression Equations ◽  
National Programmes ◽  
The Us ◽  
Level 1 ◽  
The Relationship

Background The national programmes for the harmonization of haemoglobin A1c measurement in the US and Japan are based on differently designated comparison methods. The future basis for international standardization is expected to be the reference system developed by the International Federation of Clinical Chemistry (IFCC) Working Group on haemoglobin A1c Standardization. The aim of the present study is to compare the relationship between the IFCC reference method (RM) and Japanese Diabetes Society (JDS) RM used for the conversion to the National Glycohemoglobin Standardization Program (NGSP) values. Methods Three different method-comparison studies were performed. All blood samples were measured at the National Cerebral and Cardiovascular Centers (Lipid Reference Laboratories) that serve as Level 1 reference laboratories of the NGSP Network. Regression equations were calculated for the IFCC RM and JDS RM for the conversion to NGSP values. Results Differences were found between the haemoglobin A1c values of the IFCC RM and those of JDS. However, in all cases, the relationships of the IFCC RM and JDS RM were linear and commutable. The relationship is described by the following regression equations: NGSP-HbA1c = 0.915(IFCC-HbA1c) + 2.15% (r2 = 0.998); JDS/JSCC-HbA1c = 0.927(IFCC-HbA1c) + 1.73% (r2 = 0.997). Conclusion There is a firm and reproducible link between the IFCC and JDS-HbA1c values. However, the values calibrated by JDS RM were consistently and significantly higher than the IFCC values (0.1–0.2%) when used for conversion to the NGSP values.

scholarly journals Evaluation of NG-Test Carba 5 for Rapid Phenotypic Detection and Differentiation of Five Common Carbapenemase Families: Results of a Multicenter Clinical Evaluation

2020 ◽  
Vol 58 (7) ◽  
Author(s):  
Stephen Jenkins ◽  
Nathan A. Ledeboer ◽  
Lars F. Westblade ◽  
Carey-Ann D. Burnham ◽  
Matthew L. Faron ◽  
...  
Keyword(s):  
Medical Center ◽  
Method Comparison ◽  
Reference Method ◽  
The United States ◽  
Comparison Study ◽  
Content Type ◽  
Percent Agreement ◽  
Mueller Hinton ◽  
Method Comparison Study

ABSTRACT NG-Test Carba 5 is a rapid in vitro multiplex immunoassay for the phenotypic detection and differentiation of five common carbapenemase families (KPC, OXA-48-like, VIM, IMP, and NDM) directly from bacterial colonies. The assay is simple to perform and has recently received U.S. Food and Drug Administration clearance. A method comparison study was performed at geographically diverse medical centers (n = 3) in the United States, where 309 Enterobacterales and Pseudomonas aeruginosa isolates were evaluated by NG-Test Carba 5 (NG Biotech, Guipry, France), the Xpert Carba-R assay (Cepheid, Inc., Sunnyvale, CA), the modified carbapenem inactivation method (mCIM), the EDTA-modified carbapenem inactivation method, and disk diffusion with carbapenems. Colonies from tryptic soy agar with 5% sheep blood (blood agar) and MacConkey agar were tested, and the results were compared to those obtained by a composite reference method. Additionally, a fourth medical center performed a medium comparison study by evaluating the performance characteristics of NG-Test Carba 5 from blood, MacConkey, and Mueller-Hinton agars with 110 isolates of Enterobacterales and P. aeruginosa. These results were compared to the expected genotypic and mCIM results. For the multicenter method comparison study, the overall positive percent agreement (PPA) and the overall negative percent agreement (NPA) of NG-Test Carba 5 with the composite reference method were 100% for both blood and MacConkey agars. The medium comparison study at the fourth site showed that the PPA ranged from 98.9% to 100% and that the NPA ranged from 95.2% to 100% for blood, MacConkey, and Mueller-Hinton agars. NG-Test Carba 5 accurately detected and differentiated five common carbapenemase families from Enterobacterales and P. aeruginosa colonies on commonly used agar media. The results of this test will support a streamlined laboratory work flow and will expedite therapeutic and infection control decisions.

scholarly journals Indirect Calorimetry Overestimates Oxygen Consumption in Young Children: Caution is Advised Using Direct Fick Method as a Reference Method in Cardiac Output Comparison Studies

2019 ◽  
Vol 41 (1) ◽  
pp. 149-154
Author(s):  
Theodor S. Sigurdsson ◽  
Lars Lindberg
Keyword(s):  
Cardiac Output ◽  
Oxygen Consumption ◽  
Young Children ◽  
Indirect Calorimetry ◽  
Method Comparison ◽  
Reference Method ◽  
Percentage Error ◽  
Measure Oxygen Consumption ◽  
A Minor ◽  
Method Comparison Study

AbstractDirect Fick method is considered a standard reference method for estimation of cardiac output. It relies on indirect calorimetry to measure oxygen consumption. This is important as only a minor measurement error in oxygen consumption can result in false estimation of cardiac output. A number of studies have shown that indirect calorimetry overestimates oxygen consumption in adults. The aim of this prospective single center observational method comparison study was to compare the determination of oxygen consumption by indirect calorimetry and reverse Fick method in pediatric patients. Forty-two children mean age 352 days (range 30 to 1303 days) and mean weight 7.1 kg (range 2.7–13.6 kg) undergoing corrective cardiac surgery were included in the study. The mean (standard deviation) oxygen consumption by reverse Fick method was 43.5 (16.2) ml/min and by indirect calorimetry 49.9 (18.8) ml/min (p < 0.001). Indirect calorimetry overestimated the reverse Fick oxygen consumption by 14.7%. Bias between methods was 6.5 (11.3) ml/min, limits of agreement (LOA) − 15.7 and 28.7 ml/min and percentage error of 47.7%. A significant bias and large percentage error indicates that the methods are not interchangeable. Indirect calorimetry and the direct Fick method should be used with caution as a reference method in cardiac output comparison studies in young children.

scholarly journals Evaluation of the Solus One Listeria Method for the Detection of Listeria Species on Environmental Surfaces

2019 ◽  
Vol 102 (2) ◽  
pp. 570-579
Author(s):  
Elizabeth Tonner ◽  
Siobhan Kelly ◽  
Simon Illingworth ◽  
Nevin Perera ◽  
Benjamin Bastin ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Preparation Method ◽  
Method Comparison ◽  
Reference Method ◽  
Test System ◽  
Probability Of Detection ◽  
Comparison Study ◽  
Listeria Species ◽  
Environmental Surfaces ◽  
Method Comparison Study

Abstract Background: Solus One Listeria is designed to accurately detect Listeria species (Listeria grayi, L. innocua, L. ivanovii, L. marthii, L. monocytogenes, L. seeligeri, and L. welshimeri) from stainless steel and plastic environmental surface matrixes using an antibody-based technology test system paired with proprietary SOLO+ media and combined with manual or automated sample preparation method. Objective: Solus One Listeria was evaluated for inclusivity and exclusivity and a matrix comparison study fortwo environmental surfaces. Methods: Solus One Listeria was comparedwith the following reference method for the method comparison study: the U.S. Food and Drug Administration Bacteriological Analytical Manual Chapter 10 from stainless steel and plastic environmental surfaces. Both the manual and automatedpreparation methods were performed for stainless steel and plastic environmental surfaces. Results: For the inclusivity and exclusivityevaluation, Solus One Listeria correctly identified all 50 target organism isolates and correctly excluded all 30 nontarget strains that were analyzed. In the method comparison study, bothSolus One Listeria manual and automated preparation methods demonstrated no significant differences based on probability of detection statistical analysis between presumptive and confirmed results or between candidate and reference methodresults for two environmental surfaces after 22–30 h of enrichment time. Probability of detection analysis of Solus One Listeria method robustness, product consistency (lot-to-lot), and stability studies using the automated preparation method demonstrated no statistically significant differences. Conclusions: The data from the study support the product claims of Solus One Listeria for the accurate detection of Listeria species, using both the manual and automated methods (using theDynex DS2 instrument), on both environmental surfaces analyzed.

Evaluation of carbohydrate-deficient transferrin measurements on the V8 capillary electrophoresis system and comparison with the IFCC approved HPLC reference method and N-Latex immunonephelometric assay

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Leo H.J. Jacobs ◽  
Riekie M. te Stroet ◽  
Ayse Y. Demir
Keyword(s):  
High Performance ◽  
Clinical Chemistry ◽  
Method Comparison ◽  
Reference Method ◽  
Roc Curves ◽  
Serum Samples ◽  
Roc Curve Analysis ◽  
Chronic Alcohol Abuse ◽  
Carbohydrate Deficient Transferrin ◽  
Immunonephelometric Assay

AbstractObjectivesCarbohydrate-deficient transferrin (CDT) measurements are commonly used for the identification and follow-up of individuals suspected of chronic alcohol abuse. This study describes the analytical characteristics of the CDT assay on the Helena Biosciences V8 electrophoresis analyzer and compares its diagnostic performance to the International Federation of Clinical Chemistry and Laboratory Medicine approved high performance liquid chromatography (HPLC) method and the N-Latex CDT immunonephelometric assay.MethodsThe analytical performance of the V8 assay, including the linearity and the imprecision, was studied at two separate locations. Method comparison analysis was performed by studying the correlation, bias and agreement between the V8, HPLC and the N-Latex assays in 231 patient samples.ResultsThe total imprecision ranged between 5.1 and 24.3% and was ≤13.1% for samples with concentrations above the clinical cut-off value (≥1.62%). The method comparisons revealed excellent correlations with r2≥0.97 for all comparisons. Measurements on the V8 showed a bias of −0.83 (−22.24%) and −0.40 (−12.26%) with the HPLC and N-Latex assays, respectively. The assays showed excellent agreements (Kappa scores ≥ 0.8) in classifying subjects with elevated CDT values. Receiver operating characteristic (ROC)-curve analysis, using the HPLC classification as reference, revealed areas under the ROC-curves of 0.981 (95% CI, 0.97–0.99) and 0.996 (0.99–1.00) for the N-Latex and V8 assays, respectively.ConclusionsCDT measurements on the V8 assay are highly correlated with both the HPLC and the N-Latex assay and show excellent agreement in classifying subjects with elevated CDT values. Overall, the V8 CDT analysis is a robust, reliable and effective method to measure CDT concentrations in serum samples.

scholarly journals Statistical Methods for Monitoring the Relationship between the IFCC Reference Measurement Procedure for Hemoglobin A1c and the Designated Comparison Methods in the United States, Japan, and Sweden

2008 ◽  
Vol 54 (8) ◽  
pp. 1379-1385 ◽  
Author(s):  
Andrea Geistanger ◽  
Sabine Arends ◽  
Christoph Berding ◽  
Tadao Hoshino ◽  
Jan-Olof Jeppsson ◽  
...  
Keyword(s):  
Statistical Methods ◽  
Consensus Statement ◽  
Clinical Chemistry ◽  
International Diabetes Federation ◽  
The United States ◽  
Measurement Procedure ◽  
Reference Measurement ◽  
Reference Measurement Procedure ◽  
Comparison Methods ◽  
The Relationship

Abstract Background: The American Diabetes Association (ADA)/European Association for the Study of Diabetes (EASD)/International Diabetes Federation (IDF)/IFCC Consensus Statement on the worldwide standardization of HbA1c states that “… [HbA1c] results are to be reported world-wide in IFCC units … and derived NGSP units … , using the IFCC-NGSP master equation.” Methods: We describe statistical methods to evaluate and monitor the relationships as expressed in master equations (MEs) between the IFCC Reference Measurement procedure (IFCC-RM) and designated comparison methods (DCMs) [US National Glycohemoglobin Standardization Program (NGSP), Japanese Diabetes Society/Japanese Society for Clinical Chemistry (JDS/JSCC), and Mono-S in Sweden]. We applied these statistics, including uncertainty calculations, to 12 studies in which networks of reference laboratories participated, operating the IFCC-RM and DCMs. Results: For NGSP and Mono-S, slope, intercept, and derived percentage HbA1c at the therapeutic target show compliance with the respective MEs in all 12 studies. For JDS/JSCC, a slight deviation is seen in slope and derived percentage HbA1c in 2 of the 12 studies. Using the MEs, the uncertainty in an assigned value increases from 0.42 mmol/mol HbA1c (IFCC-RM) to 0.47 (NGSP), 0.49 (JDS/JSCC), and 0.51 (Mono-S). Conclusions: We describe sound statistical methods for the investigation of relations between networks of reference laboratories. Application of these statistical methods to the relationship between the IFCC-RM and DCMs in the US, Japan, and Sweden shows that they are suitable for the purpose, and the results support the applicability of the ADA/EASD/IDF/IFCC Consensus Statement on HbA1c measurement.

Modification of the Bio-Rad iQ-Check Listeria spp. Kit for the Detection of Listeria Species in Environmental Surfaces

2020 ◽  
Vol 103 (1) ◽  
pp. 216-222
Author(s):  
Nicole Klass ◽  
Benjamin Bastin ◽  
Erin Crowley ◽  
James Agin ◽  
Mike Clark ◽  
...  
Keyword(s):  
Method Comparison ◽  
Reference Method ◽  
Culture Method ◽  
Department Of Agriculture ◽  
Listeria Species ◽  
Modified Method ◽  
Environmental Surfaces ◽  
Pcr Technology ◽  
Inspection Service ◽  
Method Comparison Study

Abstract Background: The Bio-Rad iQ-Check Listeria spp. Kit uses real-time PCR technology for detection of Listeria species in select food matrixes and environmental surfaces. Objective: The iQ-Check Listeria spp. method was modified to reduce the enrichment medium volume for environmental sponges from 225 and 100 to 60 mL and to reduce the enrichment time for sponges and swabs from 25 ± 1 to as short as 18 h. The modified method was validated with stainless steel, polystyrene plastic, and sealed concrete using sponges or swabs with two different neutralizing buffers (Letheen Broth and HiCap™ Neutralizing Broth). In addition, the Bio-Rad Free DNA Removal Solution was used for all environmental samples. Methods: The iQ-Check Listeria spp. modified method was compared with the reference culture method in the U.S. Department of Agriculture Food Safety and Inspection Service Microbiology Laboratory Guidebook Chapter 8.10 using an unpaired study design. Results: In the method comparison study, the iQ-Check Listeria spp. modified method demonstrated no statistical difference in performance between candidate and reference method results or between presumptive and confirmed results for all environmental surfaces analyzed using HiCap Neutralizing Broth (World Bioproducts LLC) and Letheen broth. Conclusions: The modified iQ-Check Listeria spp. method is an effective method for the detection of Listeria species in environmental surfaces using both types of neutralizing buffer. Highlights: The method modification was granted based on the data collected.

scholarly journals Inter-method comparison of salivary cortisol measurement

2013 ◽  
Vol 37 (5) ◽  
Author(s):  
Silvia Baecher ◽  
Shahnaz Christina Azad ◽  
Michael Vogeser
Keyword(s):  
Salivary Cortisol ◽  
Clinical Chemistry ◽  
Method Comparison ◽  
Reference Method ◽  
Substantial Improvement ◽  
Coefficients Of Variation ◽  
Liquid Chromatography Tandem Mass ◽  
Internal Standardization ◽  
Diagnostic Work ◽  
Work Up

AbstractSalivary cortisol is increasingly used in the diagnostic work-up of suspected Cushing’s disease as well as in stress research. In this study, the agreement of different methods for salivary cortisol measurement was assessed.Saliva samples from five healthy volunteers were distributed to three routine clinical chemistry laboratories. As a reference, all samples were also analyzed using liquid chromatography-tandem mass spectrometry involving stable isotope labeled cortisol for internal standardization in our laboratory.All immunometric routine methods substantially overestimated salivary cortisol concentrations by approximately 50%. The agreement between these immunoassays was moderate with between-method coefficients of variation of up to 36% for individual samples.Standardization of salivary cortisol measurement requires substantial improvement, in particular by implementation of proficiency testing schemes, a defined reference method, and reference materials. Interpretation of salivary cortisol data in psycho-neuroendocrinological research has to consider the inappropriate level of standardization realized for salivary cortisol measurement to date.

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