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Linda M Thienpont - One of the best experts on this subject based on the ideXlab platform.
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ft4 immunoassays may display a pattern during pregnancy similar to the equilibrium dialysis id lc tandem ms candidate reference Measurement Procedure in spite of susceptibility towards binding protein alterations
Clinica Chimica Acta, 2010Co-Authors: Ellen Anckaert, Kris Poppe, Kathleen Van Uytfanghe, Johan Schiettecatte, Walter Foulon, Linda M ThienpontAbstract:Abstract Background Serum free thyroxine (FT4) testing in pregnancy is known to be challenging for immunoassays (IAs). We verified the reliability of FT4 results by 3 commercial IAs throughout pregnancy, by comparison of the pattern to that obtained with an equilibrium dialysis isotope dilution–mass spectrometry (ED ID–MS) candidate reference Measurement Procedure. Methods Pregnant females (107) and age-matched non-pregnant controls (26) were enrolled. The IAs tested were those performed on the Cobas 6000 (Roche Diagnostics), ARCHITECT i2000SR (Abbott Diagnostics) and Immulite 2000 (Siemens Healthcare) platforms. Results Compared to the controls (mean FT4: 18.2 pmol/L), ED ID–MS gave in the late first trimester pregnancy an 8.8% lower ( p p p = 0.99). Similar observations were made for the Cobas and Immulite IAs. The ARCHITECT IA showed no significant decrease in the late first trimester (mean 13.5 pmol/L versus 13.6 pmol/L in controls), but a significant, less pronounced, decrease in the second and third trimesters (15% and 14.4%, respectively). All IAs were susceptible towards alterations in T4 binding proteins during pregnancy. Conclusion We proved that IAs may give a FT4 pattern during pregnancy similar to that obtained by ED ID–MS.
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proposal of a candidate international conventional reference Measurement Procedure for free thyroxine in serum
Clinical Chemistry and Laboratory Medicine, 2007Co-Authors: Linda M Thienpont, Graham Beastall, N D Christofides, James D Faix, Tamio Ieiri, V Jarrige, W G Miller, R Miller, Jerald C Nelson, Catherine RoninAbstract:In the present paper the IFCC WG-STFT recommends and provides the rationale to establish metrological traceability of serum free thyroxine (FT4) Measurements to a candidate international conventional reference Measurement Procedure. It is proposed that this Procedure be based on equilibrium dialysis combined with determination of thyroxine in the dialysate with a trueness-based reference Measurement Procedure. The measurand is thus operationally defined as "thyroxine in the dialysate from equilibrium dialysis of serum prepared under defined conditions". With regard to the trueness-based reference Measurement Procedure, the WG-STFT recommends use of an isotope dilution-liquid chromatography/tandem mass spectrometry (ID-LC/tandem MS) Procedure for total thyroxine that has been optimized towards Measurement at picomolar concentration levels and that is listed in the database of the Joint Committee for Traceability in Laboratory Medicine (JCTLM). For calibration, the purified thyroxine material IRMM-468 (resulting from a project funded by the European Commission and recently submitted to the JCTLM) is proposed. The WG-STFT stresses that according to this recommendation it is a prerequisite to strictly adhere to the defined equilibrium dialysis Procedure, whereas it is permissible to introduce variants in the ID-LC/tandem MS Procedure.
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validation of 5 routine assays for serum free testosterone with a candidate reference Measurement Procedure based on ultrafiltration and isotope dilution gas chromatography mass spectrometry
Clinical Biochemistry, 2005Co-Authors: K Van Uytfanghe, Dietmar Stockl, Jeanmarc Kaufman, Tom Fiers, A P De Leenheer, Linda M ThienpontAbstract:Abstract Background/Method: The analytical validity of free testosterone (FTe) analog immunoassays is subject to much controversy. We revisited the validation of 4 analog assays and 1 FTe calculation Procedure with a metrologically traceable reference Measurement Procedure (RMP) based on ultrafiltration and isotope dilution–mass spectrometry for direct Measurement of Te in the ultrafiltrate. To this end, we performed split-sample Measurements of 40 male sera. Results: Deming regression showed that 3 of the immunoassays had moderate to good correlation (0.8474 ≤ r ≤ 0.9241) with the RMP; however, the slope was markedly below 1. The FTe calculation Procedure was in good agreement with this result. The Sy/x values for all assays were higher than the combined imprecision values, which indicate their susceptibility to matrix-related effects. Conclusions: The study demonstrated substantial differences in analytical quality of FTe assays; however, the results suggested that after extending the validation with a larger variety of samples, recalibration of some analog assays might be worth further investigation.
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evaluation of a candidate reference Measurement Procedure for serum free testosterone based on ultrafiltration and isotope dilution gas chromatography mass spectrometry
Clinical Chemistry, 2004Co-Authors: K Van Uytfanghe, Dietmar Stockl, Tom Fiers, A P De Leenheer, Jean Kaufman, Alec H Ross, Linda M ThienpontAbstract:Background: To assess the analytical validity of free testosterone (FTe) Measurements, a reference Measurement Procedure (RMP) is required. For steroids, isotope dilution–mass spectrometry is accepted as state-of-the-art technology. Because FTe is defined as the hormone fraction in serum water in equilibrium with the protein-bound fraction, the RMP should include a physical separation step. The use of equilibrium dialysis (ED) or ultrafiltration (UF) is advocated. Our objective was to develop such a candidate RMP. Methods: We selected UF combined with isotope dilution–gas chromatography–mass spectrometry (ID-GC/MS) for direct Measurement of Te in the ultrafiltrate. After optimization of the UF process, the complete Procedure was validated by use of split-sample comparisons with indirect ED (iED) and symmetric dialysis (SyD). Results: The candidate RMP gave maximum within-day, between-day, and total CVs of 3.0%, 3.1%, and 4.3%. The Deming regression equations for the respective method comparisons were: UF-ID-GC/MS = 0.98(iED) − 53 pmol/L ( r = 0.94; S y|x = 42 pmol/L) and UF-ID-GC/MS = 0.92(SyD) + 21 pmol/L ( r = 0.97; S y|x = 31 pmol/L). Conclusions: We achieved the objective of a state-of-the-art candidate RMP, which agreed well with iED and SyD. However, we also demonstrated that a degree of discordance remains, which may require a decision from an authoritative organization on the recommended Procedure to measure free hormone concentrations.
Michael J Welch - One of the best experts on this subject based on the ideXlab platform.
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modifications to the nist reference Measurement Procedure rmp for the determination of serum glucose by isotope dilution gas chromatography mass spectrometry
Analytical and Bioanalytical Chemistry, 2010Co-Authors: Jocelyn L Prendergast, Michael J Welch, Lorna T Sniegoski, Karen W PhinneyAbstract:The definitive method (DM), now known as the reference Measurement Procedure (RMP), for the analysis of glucose in serum was originally published in 1982 by the National Institute of Standards and Technology (NIST). Over the years the method has been subject to a number of modifications to adapt to newer technologies and simplify sample preparation. We discuss here an adaptation of the method associated with serum glucose Measurements using a modified isotope dilution gas chromatography/mass spectrometry (ID-GC/MS) method. NIST has used this modified method to certify the concentrations of glucose in SRM 965b, Glucose in Frozen Human Serum, and SRM 1950, Metabolites in Human Plasma. Comparison of results from the revised method with certified values for existing Standard Reference Materials (SRMs) demonstrated that these modifications have not affected the quality of the Measurements, giving both good precision and accuracy, while reducing the sample preparation time by a day and a half.
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development and evaluation of a candidate reference Measurement Procedure for the determination of progesterone in human serum using isotope dilution liquid chromatography tandem mass spectrometry
Analytical Chemistry, 2006Co-Authors: Susan S C Tai, Michael J WelchAbstract:A candidate reference Measurement Procedure for total testosterone in human serum involving isotope dilution (ID) coupled with liquid chromatography/tandem mass spectrometry (LC/MS/MS) has been developed and critically evaluated. The endogenous testosterone and its internal standard (testosterone-d 3) were extracted from the serum matrix using a combination of solid-phase extraction and liquid–liquid extraction prior to reversed-phase LC/MS/MS. Accuracy of the Measurements was evaluated by a recovery study using testosterone-spiked serum. The recovery of the added testosterone ranged from 100.0 to 100.3%. This method was applied to the determination of testosterone in frozen serum samples from three individual donors (one female and two males) with the testosterone concentrations ranging from 0.3 to 8.5 ng g−1. Repeatability with within-set coefficients of variation (CVs) from 0.1 to 1.0% and intermediate precision with between-set CVs from 0.1 to 0.5% for both female and male serum materials were demonstrated. Excellent linearity was obtained for all linear regression lines. The detection limit at a signal-to-noise ratio of approximately 3 was 2 pg of testosterone in serum. Structural analogs as well as testosterone metabolites were tested and found to not interfere with the Measurement of testosterone. This well-characterized LC/MS/MS method for serum testosterone, which demonstrates good accuracy and precision, and low susceptibility to interferences, qualifies as a reference Measurement Procedure that can be used to provide an accuracy base to which routine methods for testosterone can be compared and that will serve as a standard of higher order for Measurement traceability.
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development and evaluation of a reference Measurement Procedure for the determination of estradiol 17β in human serum using isotope dilution liquid chromatography tandem mass spectrometry
Journal of Analytical Chemistry, 2005Co-Authors: Susan Tai S C And, Michael J WelchAbstract:Estradiol is the most potent natural estrogen and is derived from the ovaries. Its concentration in blood is measured to determine ovarian function. A reference Measurement Procedure for estradiol in serum involving isotope-dilution coupled with liquid chromatography-tandem mass spectrometry (LC/MS/MS) has been developed and critically evaluated. A deuterated estradiol (estradiol-d3) was used as an internal standard. The estradiol and its internal standard were extracted from serum matrix using solid-phase extractions and derivatized with dansyl chloride prior to reversed-phase LC/MS/MS. The accuracy of the Measurement was evaluated by a comparison of results of this reference method on lyophilized human serum reference materials for estradiol [Certified Reference Materials (CRMs) 576, 577, and 578] with the certified values determined by gas chromatography/mass spectrometry (GC/MS) reference methods and by a recovery study for the added estradiol. The results of this method for estradiol agreed with the ...
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development and evaluation of a reference Measurement Procedure for the determination of total 3 3 5 triiodothyronine in human serum using isotope dilution liquid chromatography tandem mass spectrometry
Analytical Chemistry, 2004Co-Authors: David M Bunk, E T White, Michael J WelchAbstract:3,3‘,5-Triiodothyronine (T3) is an important diagnostic marker for thyroid function. A reference Measurement Procedure (RMP) for total T3 in serum involving isotope dilution coupled with liquid chromatography−tandem mass spectrometry (LC/MS/MS) has been developed and critically evaluated. The method uses solid-phase extraction with mixed-mode retention mechanisms of reversed phase and ion exchange prior to reversed-phase LC/MS/MS. In addition to a labeled T3 internal standard (T3-13C9), labeled thyroxine (T4-d5) is also added to serum samples in order to monitor the degradation of T4 to T3. The accuracy of the Measurement was evaluated by a recovery study for added T3 and was supported by a comparison study with the other RMP. The recovery of the added T3 ranged from 98.9% to 99.4%. The results of this method and the other RMP agreed to within 1%. Samples of frozen serum pools were prepared and measured in three separate sets. Excellent reproducibility was obtained with within-set coefficients of variatio...
Karen W Phinney - One of the best experts on this subject based on the ideXlab platform.
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nhanes monitoring of serum 25 hydroxyvitamin d a roundtable summary
Journal of Nutrition, 2010Co-Authors: Elizabeth A Yetley, John H. Eckfeldt, Karen W Phinney, Rosemary L Schleicher, Christine M Pfeiffer, David A Lacher, Sylvia Christakos, James C Fleet, George Howard, Andrew N HoofnagleAbstract:A roundtable to discuss monitoring of serum 25-hydroxyvitamin D [25(OH)D] in the NHANES was held in late July 2009. Topics included the following: 1) options for dealing with assay fluctuations in serum 25(OH)D in the NHANES conducted between 1988 and 2006; 2) approaches for transitioning between the RIA used in the NHANES between 1988 and 2006 to the liquid chromatography tandem MS (LC-MS/MS) Measurement Procedure to be used in NHANES 2007 and later; 3) approaches for integrating the recently available standard reference material for vitamin D in human serum (SRM 972) from the National Institute of Standards and Technology (NIST) into the NHANES; 4) questions regarding whether the C-3 epimer of 25-hydroxyvitamin D3 [3-epi-25(OH)D3] should be measured in NHANES 2007 and later; and 5) identification of research and educational needs. The roundtable experts agreed that the NHANES data needed to be adjusted to control for assay fluctuations and offered several options for addressing this issue. The experts suggested that the LC-MS/MS Measurement Procedure developed by NIST could serve as a higher order reference Measurement Procedure. They noted the need for a commutability study for the recently released NIST SRM 972 across a range of Measurement Procedures. They suggested that federal agencies and professional organizations work with manufacturers to improve the quality and comparability of Measurement Procedures across all laboratories. The experts noted the preliminary nature of the evidence of the 3-epi-25(OH)D3 but felt that it should be measured in 2007 NHANES and later.
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modifications to the nist reference Measurement Procedure rmp for the determination of serum glucose by isotope dilution gas chromatography mass spectrometry
Analytical and Bioanalytical Chemistry, 2010Co-Authors: Jocelyn L Prendergast, Michael J Welch, Lorna T Sniegoski, Karen W PhinneyAbstract:The definitive method (DM), now known as the reference Measurement Procedure (RMP), for the analysis of glucose in serum was originally published in 1982 by the National Institute of Standards and Technology (NIST). Over the years the method has been subject to a number of modifications to adapt to newer technologies and simplify sample preparation. We discuss here an adaptation of the method associated with serum glucose Measurements using a modified isotope dilution gas chromatography/mass spectrometry (ID-GC/MS) method. NIST has used this modified method to certify the concentrations of glucose in SRM 965b, Glucose in Frozen Human Serum, and SRM 1950, Metabolites in Human Plasma. Comparison of results from the revised method with certified values for existing Standard Reference Materials (SRMs) demonstrated that these modifications have not affected the quality of the Measurements, giving both good precision and accuracy, while reducing the sample preparation time by a day and a half.
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development of a candidate reference Measurement Procedure for the determination of 25 hydroxyvitamin d3 and 25 hydroxyvitamin d2 in human serum using isotope dilution liquid chromatography tandem mass spectrometry
Analytical Chemistry, 2010Co-Authors: Mary Bedner, Karen W PhinneyAbstract:Vitamin D exists in two major forms, vitamin D3 and vitamin D2. Vitamin D helps the body absorb calcium and promote optimal bone health. Both forms of vitamin D are metabolized to 25-hydroxyvitamin D in the body, and the levels of 25-hydroxyvitamin D3 [25(OH)D3] and 25-hydroxyvitamin D2 [25(OH)D2] in serum are considered the best indicators of vitamin D status. A candidate reference Measurement Procedure for serum 25(OH)D3 and 25(OH)D2 has been developed and critically evaluated. The deuterated compounds 25(OH)D3-d3 and 25(OH)D2-d3 are used as internal standards for 25(OH)D3 and 25(OH)D2, respectively. The 25(OH)D3 and 25(OH)D2 and their respective labeled internal standards are simultaneously extracted from serum using liquid−liquid extraction prior to reversed-phase liquid chromatography−tandem mass spectrometry (LC−MS/MS). Chromatographic separation was performed using a cyano (CN) column for both 25(OH)D3 and 25(OH)D2. Atmospheric pressure chemical ionization (APCI) in the positive ion mode and multip...
Gary L. Myers - One of the best experts on this subject based on the ideXlab platform.
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the vitamin d standardization program vdsp manual for retrospective laboratory standardization of serum 25 hydroxyvitamin d data
Journal of AOAC International, 2017Co-Authors: Ramon Durazoarvizu, Gary L. Myers, Lu Tian, Stephen P J Brooks, Kurtis Sarafin, Kevin D Cashman, Mairead Kiely, Joyce Merkel, Paul M Coates, Christopher T SemposAbstract:Low concentrations of total 25-hydroxyvitamin D [25(OH)D], the principal biological measure of vitamin D status, have been associated with clinical and public health outcomes. The determination of levels under which there is an increase in the risk of disease, as well as comparisons across populations, have been difficult to establish due the large assay variability in measuring 25(OH)D. Accordingly, the Vitamin D Standardization Program (VDSP) includes the retrospective standardization of existing 25(OH)D values collected by epidemiological and clinical studies, as well as clinical trials, as one of its main objectives. We introduce methodology developed by the VDSP that can be used to standardize the Measurement of time-stable analytes, including 25(OH)D, in samples that have been banked and maintained appropriately. Sample size estimation formulae are first applied to calculate the required number of banked blood samples to be reanalyzed using either of two approaches. In the first approach, existing samples are remeasured using the current Measurement Procedure, and an equation relating "old" to "current" Measurements is obtained. A second set of sera, usually 40-50 single-donor serum samples, are measured with the current Measurement Procedure and an assay traceable to a reference Measurement Procedure and/or certified reference materials, which yields a second calibration equation. These two equations are combined to produce standardized levels from the original old values. This approach is necessary when study restrictions prevent serum samples from being shipped to an external laboratory and is illustrated with samples from the Canadian Health Measures Survey. When serum samples are permitted to be shared with other laboratories, or the study investigators can carry out the Measurements with a traceable assay, a single calibration equation method is used. Existing samples are selected and remeasured using the available traceable assay. We outline the statistical theory supporting the VDSP protocol and provide implementation examples. The methods proposed are generalizable to any instance in which banked specimens have been properly prepared and stored and the analyte of interest is stable under those conditions.
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proposed serum cholesterol reference Measurement Procedure by gas chromatography isotope dilution mass spectrometry
Clinical Chemistry, 2011Co-Authors: Selvin Edwards, Shelton L Stribling, Susan D Pyatt, Mary M Kimberly, Kara D Dobbin, Gary L. MyersAbstract:BACKGROUND: Our purpose was to establish a mass spectrometry reference Measurement Procedure (RMP) for cholesterol to use in the CDC's standardization programs. We explored a gas chromatography–isotope dilution mass spectrometry (GC-IDMS) Procedure using a multilevel standard calibration curve to quantify samples with varying cholesterol concentrations. METHODS: We calibrated the mass spectrometry instrument by isotope dilution with a pure primary standard reference material and an isotopically enriched cholesterol analog as the internal standard (IS). We diluted the serum samples with Tris-HCl buffer (pH 7.4, 0.05 mol/L, 0.25% Triton X-100) before analysis. We used 17 serum pools, 10 native samples, and 2 standard reference materials (SRMs). We compared the GC-IDMS Measurements with the CDC's modified Abell–Levy–Brodie–Kendall (AK) RMP Measurements and assessed method accuracy by analyzing 2 SRMs. We evaluated the Procedure for lack of interference by analyzing serum spiked with a mixture of 7 sterols. RESULTS: The mean percent bias between the AK and the GC-IDMS RMP was 1.6% for all samples examined. The mean percent bias from NIST's RMP was 0.5% for the SRMs. The total %CVs for SRM 1951b levels I and II were 0.61 and 0.73%, respectively. We found that none of the sterols investigated interfered with the cholesterol Measurement. CONCLUSIONS: The low imprecision, linear response, lack of interferences, and acceptable bias vs the NIST primary RMP qualifies this Procedure as an RMP for determining serum cholesterol. The CDC will adopt and implement this GC-IDMS Procedure for cholesterol standardization.
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Global standardization of glycated hemoglobin Measurement: The position of the IFCC Working Group
Clinical Chemistry and Laboratory Medicine, 2007Co-Authors: Andrea Mosca, Kor Miedema, Gary L. Myers, Randie R Little, Jan-olof Jeppsson, Hans Reinauer, W. Garry John, Ian Goodall, Tadao Hoshino, David B. SacksAbstract:The Measurement of glycated hemoglobin is central in the monitoring of glycemic control in patients with diabetes. There are at least 30 different laboratory assays commercially available to measure the proportion of HbA1c in blood. In 1995 the IFCC established a Working Group (IFCC WG-HbA1c) to achieve international standardization of HbA1c Measurement. The main achievements can be summarized as follows: a) a reference Measurement Procedure has been established with purified primary calibrators; b) a network of reference laboratories has been developed worldwide; and c) work has begun on implementation of traceability to the IFCC reference system. The IFCC WG-HbA1c recognizes the recommendation of the IFCC-IUPAC Committee on Nomenclature, Properties and Units that the analyte measured by the IFCC reference Measurement Procedure has been defined as betaN1-deoxyfructosyl-hemoglobin and that the recommended Measurement units are mmol/mol. The IFCC WG-HbA1c recommends maintaining the use of the name HbA1c in clinical practice.
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global standardization of glycated hemoglobin Measurement the position of the ifcc working group
Clinical Chemistry and Laboratory Medicine, 2007Co-Authors: Andrea Mosca, Kor Miedema, Gary L. Myers, Randie R Little, Jan-olof Jeppsson, Hans Reinauer, Ian Goodall, Tadao Hoshino, Garry W John, David B. SacksAbstract:The Measurement of glycated hemoglobin is central in the monitoring of glycemic control in patients with diabetes. There are at least 30 different laboratory assays commercially available to measure the proportion of HbA1c in blood. In 1995 the IFCC established a Working Group (IFCC WG-HbA1c) to achieve international standardization of HbA1c Measurement. The main achievements can be summarized as follows: a) a reference Measurement Procedure has been established with purified primary calibrators; b) a network of reference laboratories has been developed worldwide; and c) work has begun on implementation of traceability to the IFCC reference system. The IFCC WG-HbA1c recognizes the recommendation of the IFCC-IUPAC Committee on Nomenclature, Properties and Units that the analyte measured by the IFCC reference Measurement Procedure has been defined as beta N1-deoxyfructosyl-hemoglobin and that the recommended Measurement units are mmol/mol. The IFCC WG-HbA1c recommends maintaining the use of the name HbA1c in clinical practice. (Less)
Hans Reinauer - One of the best experts on this subject based on the ideXlab platform.
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liquid chromatography isotope dilution mass spectrometry as a new basis for the reference Measurement Procedure for hemoglobin a1c determination
Clinical Chemistry, 2010Co-Authors: Patricia Kaiser, Theodorus P M Akerboom, Rudiger Ohlendorf, Hans ReinauerAbstract:Background: Standardization of hemoglobin (Hb)A1c Measurements is a process of considerable interest for quality assurance in diabetes management. To contribute to continuous quality improvement and fulfillment of the requirements for reference Measurement Procedures according to the standards of the International Organization for Standardization, we developed a calibration system of highest metrological order using isotope dilution–mass spectrometry with a reference material. Method: Samples were prepared by enzymatic cleavage based on the IFCC reference Measurement Procedure for LC-MS analysis. After digestion the samples were spiked with [D7]-labeled glycated and nonglycated hexapeptides as internal standards for quantification. LC-MS analysis was performed by using a C12 reversed-phase column and a gradient of acetonitrile/H2O containing 0.1% formic acid. Results: Calibration systems for HbA1c determination based on liquid chromatography–isotope dilution–mass spectrometry (LC-ID-MS) and on the IFCC reference Measurement Procedure were compared. A linear regression analysis demonstrated a correlation of r 2 = 1.00 between the 2 different calibration systems. Mean deviation was 5.5% for the calibration and 3.3% for hemolysate samples, with a mean expanded uncertainty of 4.9%. Conclusions: This LC-ID-MS Procedure allows the current IFCC reference Measurement Procedure for HbA1c to be raised to a higher order of accuracy.
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Global standardization of glycated hemoglobin Measurement: The position of the IFCC Working Group
Clinical Chemistry and Laboratory Medicine, 2007Co-Authors: Andrea Mosca, Kor Miedema, Gary L. Myers, Randie R Little, Jan-olof Jeppsson, Hans Reinauer, W. Garry John, Ian Goodall, Tadao Hoshino, David B. SacksAbstract:The Measurement of glycated hemoglobin is central in the monitoring of glycemic control in patients with diabetes. There are at least 30 different laboratory assays commercially available to measure the proportion of HbA1c in blood. In 1995 the IFCC established a Working Group (IFCC WG-HbA1c) to achieve international standardization of HbA1c Measurement. The main achievements can be summarized as follows: a) a reference Measurement Procedure has been established with purified primary calibrators; b) a network of reference laboratories has been developed worldwide; and c) work has begun on implementation of traceability to the IFCC reference system. The IFCC WG-HbA1c recognizes the recommendation of the IFCC-IUPAC Committee on Nomenclature, Properties and Units that the analyte measured by the IFCC reference Measurement Procedure has been defined as betaN1-deoxyfructosyl-hemoglobin and that the recommended Measurement units are mmol/mol. The IFCC WG-HbA1c recommends maintaining the use of the name HbA1c in clinical practice.
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global standardization of glycated hemoglobin Measurement the position of the ifcc working group
Clinical Chemistry and Laboratory Medicine, 2007Co-Authors: Andrea Mosca, Kor Miedema, Gary L. Myers, Randie R Little, Jan-olof Jeppsson, Hans Reinauer, Ian Goodall, Tadao Hoshino, Garry W John, David B. SacksAbstract:The Measurement of glycated hemoglobin is central in the monitoring of glycemic control in patients with diabetes. There are at least 30 different laboratory assays commercially available to measure the proportion of HbA1c in blood. In 1995 the IFCC established a Working Group (IFCC WG-HbA1c) to achieve international standardization of HbA1c Measurement. The main achievements can be summarized as follows: a) a reference Measurement Procedure has been established with purified primary calibrators; b) a network of reference laboratories has been developed worldwide; and c) work has begun on implementation of traceability to the IFCC reference system. The IFCC WG-HbA1c recognizes the recommendation of the IFCC-IUPAC Committee on Nomenclature, Properties and Units that the analyte measured by the IFCC reference Measurement Procedure has been defined as beta N1-deoxyfructosyl-hemoglobin and that the recommended Measurement units are mmol/mol. The IFCC WG-HbA1c recommends maintaining the use of the name HbA1c in clinical practice. (Less)
