scholarly journals External Quality Assessment for the Detection of Chlamydia trachomatis in Urine Using Molecular Techniques in Belgium

2015 ◽  
Vol 2015 ◽  
pp. 1-8
Author(s):  
Bernard China ◽  
Kris Vernelen
Keyword(s):  
Chlamydia Trachomatis ◽  
Quality Assessment ◽  
External Quality Assessment ◽  
Molecular Techniques ◽  
Nucleic Acid Amplification ◽  
Bacterial Disease ◽  
External Quality ◽  
Sexually Transmitted ◽  
Low Sensitivity

Chlamydia trachomatis is a major cause of sexually transmitted bacterial disease worldwide. C. trachomatis is an intracellular bacterium and its growth in vitro requires cell culture facilities. The diagnosis is based on antigen detection and more recently on molecular nucleic acid amplification techniques (NAAT) that are considered fast, sensitive, and specific. In Belgium, External Quality Assessment (EQA) for the detection of C. trachomatis in urine by NAAT was introduced in 2008. From January 2008 to June 2012, nine surveys were organized. Fifty-eight laboratories participated in at least one survey. The EQA panels included positive and negative samples. The overall accuracy was 75.4%, the overall specificity was 97.6%, and the overall sensitivity was 71.4%. Two major issues were observed: the low sensitivity (45.3%) for the detection of low concentration samples and the incapacity of several methods to detect the Swedish variant of C. trachomatis. The reassuring point was that the overall proficiency of the Belgian laboratories tended to improve over time.

scholarly journals The versatility of external quality assessment for the surveillance of laboratory and in vitro diagnostic performance: SARS-CoV-2 viral genome detection in Austria

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Christoph Buchta ◽  
Jeremy V. Camp ◽  
Jovana Jovanovic ◽  
Peter Chiba ◽  
Elisabeth Puchhammer-Stöckl ◽  
...  
Keyword(s):  
Quality Assessment ◽  
External Quality Assessment ◽  
False Negative ◽  
Positive Sample ◽  
Performance Criteria ◽  
External Quality ◽  
Assay Sensitivity ◽  
Dilution Series ◽  
Test Systems

Abstract Objectives External quality assessment (EQA) schemes provide information on individual and general analytical performance of participating laboratories and test systems. The aim of this study was to investigate the use and performance of SARS-CoV-2 virus genome detection systems in Austrian laboratories and their preparedness to face challenges associated with the pandemic. Methods Seven samples were selected to evaluate performance and estimate variability of reported results. Notably, a dilution series was included in the panel as a measure of reproducibility and sensitivity. Several performance criteria were evaluated for individual participants as well as in the cohort of all participants. Results A total of 109 laboratories participated and used 134 platforms, including 67 different combinations of extraction and PCR platforms and corresponding reagents. There were no false positives and 10 (1.2%) false negative results, including nine in the weakly positive sample (C t ∼35.9, ∼640 copies/mL). Twenty (22%) laboratories reported results of mutation detection. Twenty-five (19%) test systems included amplification of human RNA as evidence of proper sampling. The overall linearity of C t values from individual test systems for the dilution series was good, but inter-assay variability was high. Both operator-related and systematic failures appear to have caused incorrect results. Conclusions Beyond providing certification for participating laboratories, EQA provides the opportunity for participants to evaluate their performance against others so that they may improve operating procedures and test systems. Well-selected EQA samples offer additional inferences to be made about assay sensitivity and reproducibility, which have practical applications.

scholarly journals External Quality Assessment for the Determination of Diphtheria Antitoxin in Human Serum

2010 ◽  
Vol 17 (8) ◽  
pp. 1282-1290 ◽  
Author(s):  
Paolo Di Giovine ◽  
Antonella Pinto ◽  
Rose-Marie Ölander ◽  
Dorothea Sesardic ◽  
Paul Stickings ◽  
...  
Keyword(s):  
Quality Assessment ◽  
External Quality Assessment ◽  
Accurate Determination ◽  
Enzyme Linked Immunosorbent Assay ◽  
Reference Laboratory ◽  
Routine Method ◽  
External Quality ◽  
Passive Hemagglutination

ABSTRACT Accurate determination of diphtheria toxin antibodies is of value in determining the rates of immunity within broad populations or the immune status of individuals who may be at risk of infection, by assessing responses to vaccination and immunization schedule efficacy. Here we report the results of an external quality assessment (EQA) study for diphtheria serology, performed within the dedicated surveillance network DIPNET. Twelve national laboratories from 11 European countries participated by testing a standard panel of 150 sera using their current routine method: Vero cell neutralization test (NT), double-antigen enzyme-linked immunosorbent assay (ELISA; DAE), dual double-antigen time-resolved fluorescence immunoassay (dDA-DELFIA), passive hemagglutination assay (PHA), toxin binding inhibition assay (ToBI), and in-house or commercial ELISAs. The objective of the study was not to identify the best assay, as the advantages and drawbacks of methods used were known, but to verify if laboratories using their routine method would have categorized (as negative, equivocal, or positive) a serum sample in the same way. The performance of each laboratory was determined by comparing its results on a quantitative and qualitative basis to NT results from a single reference laboratory, as this test is considered the in vitro “gold standard.” The performance of laboratories using NT was generally very good, while the laboratories’ performance using other in vitro methods was variable. Laboratories using ELISA and PHA performed less well than those using DAE, dDA-DELFIA, or ToBI. EQA is important for both laboratories that use in vitro nonstandardized methods and those that use commercial ELISA kits.

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