First results of a national external quality assessment scheme for the detection of SARS-CoV-2 genome sequences Beliebt

A total of 52 laboratories participated, contributing results from 67 test panels comprising 42 distinct combinations of NA extraction and PCR reagents. By testing 3 positive (CT values: S1, 28.4; S2, 33.6; S3, 38.5) and 1 negative sample, no false-positive results were obtained by any of the laboratories. Otherwise, 40/67 tests (60 %) detected all positive samples correctly as positive, but 25/67 tests (37 %) did not detect the weakest positive sample (S3), and 3 % reported S2 and S3 as false-negative. Improvement in test sensitivity by focusing on NA extraction and/or PCR-based detection is recommended.

IFCC Guidelines molekulare SARS-2 Testung Beliebt

The diagnosis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection globally has relied extensively on molecular testing, contributing vitally to case identification, isolation, contact tracing, and rationalization of infection control measures during the coronavirus disease 2019 (COVID-19) pandemic.

IFCC Guidelines serolog SARS-2 Testung Beliebt

Serological testing for the detection of antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is emerging as an important component of the clinical management of patients with coronavirus disease 2019 (COVID-19) as well as the epidemiological assessment of SARS-CoV-2 exposure worldwide.

ÖGLMC ÖQUASTA VOC 2021-02-15 Beliebt

Die molekulargenetische Detektion von SARS-CoV-2 Varianten ist essentiell, um die Ausbreitung von Variants of Concern (VOC) zu beobachten und durch geeignete Maßnahmen einzudämmen. Von praktischer Relevanz sind derzeit vor allem B.1.1.7 - „britische“ VOC, B.1.351 - „südafrikanische“ VOC, B.1.1.28 - „brasilianische“ VOC. Die Anordnung alle Proben mit erstmalig positivem SARS-CoV-2 PCR-Befund auf das Vorliegen von Mutationen zu untersuchen, wird von der ÖGLMKC und der ÖQUASTA vollinhaltlich unterstützt.

Variability of cycle threshold values in an external quality assessment scheme for detection of the SARS-CoV-2 virus genome by RT-PCR

A total of 66 laboratories participated, contributing results from 101 distinct test systems and reporting Ct values for a total of 92 different protocols. In all three positive samples, the means of the Ct values for the E-, N-, S-, RdRp-, and ORF1ab-genes varied by less than two cycles. However, 7.7% of reported results deviated by more than ±4.0 (maximum 18.0) cycles from the respective individual means. These larger deviations appear to be systematic errors.
In an attempt to use PCR diagnostics beyond the identification of infected individuals, laboratories are frequently requested to report Ct values along with a qualitative result. This study highlights the limitations of interpreting Ct values from the various SARS-CoV genome detection protocols and suggests that standardization isnecessary in the reporting of Ct values with respect to the target gene.

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