scholarly journals Performance and System Validation of a New Cellular-Enabled Blood Glucose Monitoring System Using a New Standard Reference Measurement Procedure of Isotope Dilution UPLC-MRM Mass Spectrometry

2015 ◽  
Vol 9 (5) ◽  
pp. 1061-1070 ◽  
Author(s):  
Kimon Angelides ◽  
Risë K. Matsunami ◽  
David A. Engler
Keyword(s):  
Mass Spectrometry ◽  
Blood Glucose ◽  
Monitoring System ◽  
Isotope Dilution ◽  
Glucose Monitoring ◽  
Measurement Procedure ◽  
Blood Glucose Monitoring ◽  
Reference Measurement ◽  
System Validation ◽  
Reference Measurement Procedure

scholarly journals Proposed Serum Cholesterol Reference Measurement Procedure by Gas Chromatography–Isotope Dilution Mass Spectrometry

2011 ◽  
Vol 57 (4) ◽  
pp. 614-622 ◽  
Author(s):  
Selvin H Edwards ◽  
Mary M Kimberly ◽  
Susan D Pyatt ◽  
Shelton L Stribling ◽  
Kara D Dobbin ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Serum Cholesterol ◽  
Isotope Dilution ◽  
Isotope Dilution Mass Spectrometry ◽  
Measurement Procedure ◽  
Standard Reference Materials ◽  
Reference Measurement ◽  
Reference Measurement Procedure ◽  
The Mean

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.

scholarly journals Feasibility of Standardization of Serum C-Peptide Immunoassays with Isotope-Dilution Liquid Chromatography–Tandem Mass Spectrometry

2006 ◽  
Vol 52 (6) ◽  
pp. 1193-1196 ◽  
Author(s):  
Diego Rodríguez Cabaleiro ◽  
Dietmar Stöckl ◽  
Jean M Kaufman ◽  
Tom Fiers ◽  
Linda M Thienpont
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Isotope Dilution ◽  
Method Comparison ◽  
Measurement Procedure ◽  
Tandem Ms ◽  
C Peptide ◽  
Reference Measurement ◽  
Reference Measurement Procedure ◽  
Lc Tandem Ms

Abstract Background: Serum C-peptide concentrations reflect pancreatic function in different clinical and diagnostic settings; however, the utility of C-peptide testing is limited by the lack of standardized commercial immunoassays. Standardization can best be done by split-sample comparison with a hierarchically higher reference measurement procedure with a set of native sera. For serum peptides, isotope-dilution liquid chromatography–mass spectrometry (ID-LC/MS) is recommended as a reference measurement procedure. Methods: We evaluated the analytical performance characteristics of an ID-LC/tandem MS procedure for measurement of serum C-peptide after a 2-step solid-phase extraction. To investigate the feasibility of this procedure for use in standardization, we also performed a method comparison with 3 representative commercial assays. Results: The ID-LC/tandem MS procedure showed maximum within-run, between-run, and total CVs on dedicated sera (C-peptide concentrations, 1.6 and 4.0 μg/L) of 2.1%, 2.5%, and 2.9%, respectively; an accuracy of 94.6%–104.1%; a minimum trueness of 98.1% (95% confidence interval, 96.2%–100.0%), and limits of quantification and detection of 0.15 and 0.03 μg/L, respectively. Deming linear regression analysis of the method-comparison data showed that the immunoassays correlated well with ID-MS and were specific, but lacked intercomparability and trueness. We propose that the deficiencies can be resolved by recalibration on the basis of the method comparison. Conclusions: The ID-LC/tandem MS procedure is suitable for specific and accurate measurement of basal and stimulated serum concentrations of proinsulin C-peptide fragment 33–63 and is suitable for use in standardization of C-peptide immunoassays.

scholarly journals Measurement of Urea in Human Serum by Isotope Dilution Mass Spectrometry: A Reference Procedure

1999 ◽  
Vol 45 (9) ◽  
pp. 1523-1529 ◽  
Author(s):  
Anja Kessler ◽  
Lothar Siekmann
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Human Serum ◽  
Isotope Dilution ◽  
Accurate Determination ◽  
Measurement Procedure ◽  
Gas Chromatography Mass Spectrometry ◽  
Reference Measurement ◽  
Chromatography Mass Spectrometry ◽  
Reference Measurement Procedure

Abstract Background: A reference measurement procedure is needed to demonstrate the traceability of results of urea measurements in human serum. We developed a measurement procedure using the principle of isotope dilution gas chromatography/mass spectrometry. Methods: [13C,15N2]Urea as internal standard was added to a serum sample and equilibrated with endogenous nonlabeled urea. For the preparation of calibrators, the same amount of labeled urea was mixed with known amounts of nonlabeled urea. The serum samples were treated with ethanol to remove proteins by precipitation. The labeled and nonlabeled urea of the samples was converted into a trimethylsilyl derivative of 2-hydroxypyrimidine. The gas chromatography/mass spectrometry system was adjusted to monitor m/z 153 and 168 for the nonlabeled urea derivative and m/z 156 and 171 for the isotopically labeled analogs. The results of the determination were calculated from peak ratios by a hyperbolic calculation function based on the theory of isotope dilution analysis. Results: The procedure was applied to control samples and patient samples and evaluated with respect to its trueness and precision. The standard uncertainty of the results was 0.47–1.72%. Conclusions:This reference measurement procedure allows values to be assigned to controls and calibrators that are traceable to the primary urea reference material of NIST and, therefore, to the Système International unit “mole” with a low degree of uncertainty. This procedure provides a tool for the highly accurate determination of urea in control materials as well as in patient sera.

scholarly journals Impact of Two Different Reference Measurement Procedures on Apparent System Accuracy of 18 CE-Marked Current-Generation Blood Glucose Monitoring Systems

2020 ◽  
pp. 193229682094887
Author(s):  
Guido Freckmann ◽  
Annette Baumstark ◽  
Nina Jendrike ◽  
Jochen Mende ◽  
Sebastian Schauer ◽  
...  
Keyword(s):  
Blood Glucose ◽  
Measurement Accuracy ◽  
Glucose Monitoring ◽  
Measurement Procedure ◽  
Blood Glucose Monitoring ◽  
Monitoring Systems ◽  
Reference Measurement ◽  
Comparison Methods ◽  
The Impact ◽  
Apparent Level

Background: Measurement accuracy has been assessed for many different blood glucose monitoring systems (BGMS) over the years by different study groups. However, the choice of the comparison measurement procedure may impact the apparent level of accuracy found in such studies. Materials and Methods: Measurement accuracy of 18 different BGMS was assessed in a setting based on ISO 15197 using two different comparison methods in parallel: a glucose oxidase (GOD)-based and a hexokinase (HK)-based method. Accuracy limits of ISO 15197 were applied, and additional analyses were performed, including bias, linear regression, and mean absolute relative difference (MARD) to assess the impact of possible differences between comparison methods on the apparent level of accuracy. Results: While ≈80% of BGMS met the accuracy criteria of ISO 15197 when compared with the respective manufacturers’ reference measurement procedure, only two-thirds did so against both comparison methods. The mean relative bias ranged from −6.6% to +5.7% for the analysis against the GOD-based method and from −11.1% to +1.3% for the analysis against the HK-based method, whereas MARD results ranged from 3.7% to 9.8% and from 2.3% to 10.5%, respectively. Results of regression analysis showed slopes between 0.85 and 1.08 (GOD-based method) and between 0.81 and 1.01 (HK-based method). Conclusions: The results of this study indicate that there are systematic differences between the reference measurement procedures used for BGMS calibration as well as for system accuracy assessment. Because of the potential impact on therapy of patients with diabetes resulting from these differences, further steps toward harmonization of the measurement procedures’ results are important.

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