scholarly journals IFCC Working Group Recommendations for Assessing Commutability Part 2: Using the Difference in Bias between a Reference Material and Clinical Samples

2018 ◽  
Vol 64 (3) ◽  
pp. 455-464 ◽  
Author(s):  
Göran Nilsson ◽  
Jeffrey R Budd ◽  
Neil Greenberg ◽  
Vincent Delatour ◽  
Robert Rej ◽  
...  
Keyword(s):  
Reference Material ◽  
Quality Assessment ◽  
Working Group ◽  
External Quality Assessment ◽  
Clinical Samples ◽  
External Quality ◽  
Amount Of Substance ◽  
Specific Effects ◽  
Fit For Purpose ◽  
The Difference

Abstract A process is described to assess the commutability of a reference material (RM) intended for use as a calibrator, trueness control, or external quality assessment sample based on the difference in bias between an RM and clinical samples (CSs) measured using 2 different measurement procedures (MPs). This difference in bias is compared with a criterion based on a medically relevant difference between an RM and CS results to make a conclusion regarding commutability. When more than 2 MPs are included, the commutability is assessed pairwise for all combinations of 2 MPs. This approach allows the same criterion to be used for all combinations of MPs included in the assessment. The assessment is based on an error model that allows estimation of various random and systematic sources of error, including those from sample-specific effects of interfering substances. An advantage of this approach is that the difference in bias between an RM and the average bias of CSs at the concentration (i.e., amount of substance present or quantity value) of the RM is determined and its uncertainty estimated. An RM is considered fit for purpose for those MPs for which commutability is demonstrated.

Evaluation of the ARKRAY HA-8190V instrument for HbA1c

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Eline A.E. van der Hagen ◽  
Sanne Leppink ◽  
Karin Bokkers ◽  
Carla Siebelder ◽  
Cas W. Weykamp
Keyword(s):  
Quality Assessment ◽  
Concentration Level ◽  
External Quality Assessment ◽  
Clinical Samples ◽  
Diabetic Patients ◽  
External Quality ◽  
Target Values ◽  
Performance Specifications ◽  
Certification Programme ◽  
And Performance

Abstract Objectives Hemoglobin A1c (HbA1c) is a valuable parameter in the monitoring of diabetic patients and increasingly in diagnosis of diabetes. Manufacturers continuously optimize instruments, currently the main focus is to achieve faster turnaround times. It is important that performance specifications remain of high enough standard, which is evaluated in this study for the new ARKRAY HA-8190V instrument. Methods The Clinical and Laboratory Standards Institute (CLSI) protocols EP-5, EP-9 and EP-10 were applied to investigate imprecision, bias and linearity. In addition potential interferences, performance in External Quality Assessment (EQA) and performance against the HA-8180V instrument in 220 clinical samples was evaluated. Results The HA-8190V demonstrates a CV of ≤0.8% in IFCC SI units (≤0.6% National Glycohemoglobin Standardization Program [NGSP]) at 34 and 102 mmol/mol levels (5.3 and 11.5% NGSP) and a bias of −0.1 mmol/mol (−0.01% NGSP) at a concentration of 50 mmol/mol (6.7% NGSP), but with a significant slope as compared to target values. This results in a bias of −1.0 and 0.9 mmol/mol (−2.0 and 0.9% NGSP) at the 30 and 70 mmol/mol (4.9 and 8.6% NGSP) concentration level. Simulation of participation in the IFCC certification programme results in a Silver score (bias −0.1 mmol/mol, CV 1.1%). Interference in the presence of the most important Hb variants (AS, AC, AE, AD) and elevated HbA2 and HbF concentrations is less than 3 mmol/mol (0.3% NGSP) at a concentration of 50 mmol/mol (6.7% NGSP). Conclusions Analytical performance of the HA-8190V is very good, especially with respect to precision and HbA1c quantification in the presence of the most common Hb variants.

Degradation of vancomycin in external quality assessment samples is a factor to underestimate its concentration

Bioanalysis ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 1743-1750
Author(s):  
Yaxin Fan ◽  
Yu Wang ◽  
Mengting Chen ◽  
Yuancheng Chen ◽  
Beining Guo ◽  
...  
Keyword(s):  
High Temperature ◽  
Quality Assessment ◽  
External Quality Assessment ◽  
Degradation Products ◽  
Fluorescence Polarization Immunoassay ◽  
External Quality ◽  
Target Values ◽  
The Difference ◽  
Chromatographic Peaks

Aim: To compare the difference between the measured and target values in vancomycin external quality assessment (EQA) samples and to investigate the factors for underestimating its concentration. Materials & methods: A retrospective analysis of 195 international vancomycin EQA results was performed. Deviations of the concentrations determined by TDx fluorescence polarization immunoassay (FPIA), Axsym FPIA and Architect chemiluminescence microparticle immunoassay (CMIA) method were -2.43, -16.28 and -10.53%, respectively. Chromatographic peaks of the crystalling degradation products appeared in samples with large deviations. Vancomycin were degraded after long-term transporting and high temperature. Conclusion: Vancomycin concentrations measured by Axsym FPIA and Architect CMIA methods were likely to be underestimated. Long-term transporting resulted in low EQA results, suggesting that establishing a local EQA system for vancomycin is essential.

External Quality Assessment in The Netherlands: time to introduce commutable survey specimens. Lessons from the Dutch “Calibration 2000” project

2005 ◽  
Vol 43 (3) ◽  
Author(s):  
Henk Baadenhuijsen ◽  
Aldy Kuypers ◽  
Cas Weykamp ◽  
Christa Cobbaert ◽  
Rob Jansen
Keyword(s):  
Reference Material ◽  
The Netherlands ◽  
Quality Assessment ◽  
External Quality Assessment ◽  
Accuracy Assessment ◽  
Reference Method ◽  
Field Method ◽  
External Quality ◽  
Wet Chemistry ◽  
Eqa Schemes

AbstractThe performance of suitable secondary reference material for the use of trueness control of six routinely measured clinical enzymes in the Dutch External Quality Assessment (EQA) scheme is described. The reference material of choice was selected using the split-patient-sample between-field method (twin study) design as described in an earlier study of the Calibration 2000 project in The Netherlands. This material, which was proven to be commutable for all wet chemistry systems, was implemented as the national enzyme calibrator. It consisted of a cryo-protected lyophilised serum with additions of recombinant human enzymes. Various batches of the frozen version of this material without cryo-protection additive, called native EQA samples, were used in the general EQA scheme for performance evaluation. The results of Calibration 2000 calibrated and non-Calibration 2000 calibrated laboratories were compared for both the regular (spiked with non-human enzymes) and native EQA samples in terms of precision and bias with established reference method values for the native samples. The regular samples showed mean between-laboratory CV ranges for all six enzymes involved (low–high) of 5.5–10.3% for the non-calibrated users vs. 4.6–10.8% for the calibrated users. For the native samples these respective ranges were 5.2–9.9% vs. 2.2–4.9%. Without exception, the group of Calibration 2000 calibrated users showed the lowest bias against the reference method values. Regular EQA samples (spiked with non-human enzymes) showed poorer performance than native samples and are not suitable for accuracy assessment purposes, the main aim of EQA schemes. Native samples that are commutable should be used for trueness control in current EQA schemes.

scholarly journals The Importance of Commutability of Reference Materials Used as Calibrators: The Example of Ceruloplasmin

2013 ◽  
Vol 59 (9) ◽  
pp. 1322-1329 ◽  
Author(s):  
Ingrid Zegers ◽  
Robert Beetham ◽  
Thomas Keller ◽  
Joanna Sheldon ◽  
David Bullock ◽  
...  
Keyword(s):  
Reference Material ◽  
Quality Assessment ◽  
Reference Materials ◽  
External Quality Assessment ◽  
Serum Samples ◽  
External Quality ◽  
Measurement Results ◽  
Materials Used ◽  
The Uk ◽  
Good Linear Correlation

BACKGROUND Different methods for ceruloplasmin tend to give different results in external quality assessment schemes. During the production of the certified reference material ERM-DA470k/IFCC discrepant measurement results were also found for ceruloplasmin measured with different methods, and consequently the protein could not be certified in the material. METHODS We performed a commutability study with 30 serum samples and the reference materials ERM-DA470, ERM-DA470k/IFCC, and ERM-DA472/IFCC, using 6 different methods. Data were analyzed according to the CLSI Guideline C53-A to assess whether the reference materials had the same behavior as the serum samples with respect to measurement results obtained with combinations of the methods used. RESULTS Measurement results from different methods showed a good linear correlation for the serum samples. ERM-DA470 showed marked noncommutability for certain combinations of methods. ERM-DA470k/IFCC and ERM-DA472/IFCC were commutable for more combinations of methods. The lack of commutability of ERM-DA470 for certain combinations of methods correlates with results from the UK National External Quality Assessment Service showing discrepancies between results from these methods. For serum stored in the presence of sodium azide the results from different methods are essentially equivalent. CONCLUSIONS Ceruloplasmin in ERM-DA470 is a fully documented example of a situation in which, due to lack of commutability, the use of a common material for calibration did not lead to harmonization .

Baseline Assessment of 25-Hydroxyvitamin D Reference Material and Proficiency Testing/External Quality Assurance Material Commutability: A Vitamin D Standardization Program Study

2017 ◽  
Vol 100 (5) ◽  
pp. 1288-1293 ◽  
Author(s):  
Karen W Phinney ◽  
Christopher T Sempos ◽  
Susan S-C Tai ◽  
Johanna E Camara ◽  
Stephen A Wise ◽  
...  
Keyword(s):  
Vitamin D ◽  
Quality Assurance ◽  
Reference Material ◽  
Quality Assessment ◽  
Human Serum ◽  
Proficiency Testing ◽  
External Quality Assessment ◽  
External Quality ◽  
Hydroxyvitamin D ◽  
25 Hydroxyvitamin D

Abstract The Vitamin D Standardization Program (VDSP) coordinated a study in 2012 to assess the commutability of reference materials and proficiency testing/external quality assurance materials for total 25-hydroxyvitamin D [25(OH)D] in human serum, the primary indicator of vitamin D status. A set of 50 single-donor serum samples as well as 17 reference and proficiency testing/external quality assessment materials wereanalyzed by participating laboratories that used either immunoassay or LC-MS methods for total 25(OH)D. The commutability test materials included National Institute of Standards and Technology Standard Reference Material 972a Vitamin D Metabolites in Human Serum as well as materials from the College of AmericanPathologists and the Vitamin D External Quality Assessment Scheme. Study protocols and data analysis procedures were in accordance with Clinical and Laboratory Standards Institute guidelines. The majority of the test materials were found to be commutable with the methods used in this commutability study. These results provide guidance for laboratories needing tochoose appropriate reference materials and select proficiency or external quality assessment programs and will serve as a foundation for additional VDSP studies.

Sign in / Sign up

Export Citation Format

Share Document