scholarly journals Serological diagnostic for SARS-CoV-2: an experimental External Quality Assessment Scheme

Author(s):  
Laura Sciacovelli ◽  
Andrea Padoan ◽  
Sandra Secchiero ◽  
Mario Plebani

Abstract Objectives Numerous analytical systems, rapidly made available on the market throughout the SARS-CoV-2 pandemic, aim to detect COVID-19, and to continuously update and improve the same systems. Medical laboratory professionals have also developed in-house analytical procedures in order to satisfy the enormous volume of requests for tests. These developments have highlighted the need control the analytical procedures used in order to guarantee patient safety. The External Quality Assessment (EQA) Scheme, an important quality assurance tool, aims to guarantee high standard performance for laboratory and analytical procedures. The aim of the present study was to report on the results collected in an experimental EQA scheme for the serological diagnosis of SARS-CoV-2. Methods All qualitative results collected in the different EQA surveys were summarized in order to identify the percentage of laboratory results in relation to typology of antibodies, results and samples. Results A total of 4,867 data sets were collected. The analysis of EQA data made, demonstrates a better agreement among laboratories results for total Ig than single immunoglobulins (IgG, IgM, IgA) in the case samples positive for SARS-CoV-2, and a wide divergence between IgM results for positive samples (only 34.9% were correct). Results for negative controls and specificity controls demonstrated a better overall agreement than results for positive samples. Conclusions Working in collaboration with the IVD manufacturers, laboratory professionals must strive to achieve harmonization of results, and to develop well-defined protocols complying with the ISO 15189 requirements.

2017 ◽  
Vol 100 (5) ◽  
pp. 1277-1287 ◽  
Author(s):  
Carolyn Q Burdette ◽  
Johanna E Camara ◽  
Federica Nalin ◽  
Jeanita Pritchett ◽  
Lane C Sander ◽  
...  

Abstract Until recently, the Vitamin D External Quality Assessment Scheme (DEQAS) assessed the performance of various assays for the determination of serum total 25-hydroxyvitamin D [25(OH)D] by using a consensus mean based on the all-laboratory trimmed mean (ALTM) of the approximately 1000 participants' results. Since October 2012, the National Institute of Standardsand Technology (NIST), as part of the Vitamin D Standardization Program, has participated in DEQAS by analyzing the quarterly serum sample sets using an isotope dilution LC-tandem MS (ID LC-MS/MS) reference measurement procedure to assign an accuracy-based target value for serum total 25(OH)D. NIST has analyzed90 DEQAS samples (18 exercises × 5 samples/exercise) to assign target values. The NIST-assigned values are compared with the ALTM and the biases assessed for various assays used by the participants, e.g., LC-MS/MS, HPLC, and several ligand-binding assays. The NIST-value assignment process and the resultsof the analyses of the 90 DEQAS samples are summarized. The absolute mean bias between the NIST-assignedvalues and the ALTM was 5.6%, with 10% of the samples having biases >10%. Benefits of the accuracy-based target values are presented, including for sample sets with high concentrations of 25(OH)D2 and 3-epi-25(OH)D3.


Author(s):  
Chao-Yang Chen ◽  
Meng-Ya Li ◽  
Ling-Yun Ma ◽  
Xing-Yu Zhai ◽  
Dao-Huang Luo ◽  
...  

Abstract Background Vancomycin remains a mainstay of the treatment of Gram-positive bacterial infections. It is crucial to accurately determine vancomycin serum concentration for adequate dose adjustment. Objectives To evaluate the precision and accuracy of commercial assay techniques for vancomycin concentration and to assess the comparability of vancomycin detection methods in Chinese laboratories. Methods Human serum samples spiked with known concentrations of vancomycin were provided to laboratories participating in the external quality assessment scheme (EQAS). Assay methods included chemiluminescence, enzyme immunoassay (EIA) and so on. The dispersion of the measurements was analysed and the robust coefficient of variation (rCV), relative percentage difference (RPD) and satisfactory rate for method groups were calculated. Moreover, performance of the Chinese laboratories was assessed. Results A total of 657 results from 75 laboratories were collected, including 84 samples from 10 Chinese laboratories. The median rCV, median RPD and satisfactory rates classified by methods ranged from 1.85% to 15.87%, −14.75% to 13.34% and 94.59% to 100.00%, respectively. Significant differences were seen in precision, between kinetic interaction of microparticles in solution (KIMS) and other methods, and in accuracy, between enzyme-multiplied immunoassay technique (EMIT), fluorescence polarization immunoassay (FPIA) and other techniques. Vancomycin detection in China mainly depended on the chemiluminescence and EMIT methods, which tended to result in lower measurements. Conclusions Although almost all assays in this study achieved an acceptable performance for vancomycin serum concentration monitoring, obvious inconsistencies between methods were still observed. Chinese laboratories were more likely to underestimate vancomycin concentrations. Thus, recognizing inconsistencies between methods and regular participation in vancomycin EQAS are essential.


2008 ◽  
Vol 182 (1-3) ◽  
pp. 35-40 ◽  
Author(s):  
M. Ventura ◽  
R. Ventura ◽  
S. Pichini ◽  
S. Leal ◽  
P. Zuccaro ◽  
...  

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