External quality assessments for SARS-CoV-2 genome detection in Austria : A comparison of the first postpandemic round with results from the pandemic era

Christoph Buchta ¹, Stephan W Aberle ², Irene Görzer ²

⁰Austrian Association for Quality Assurance and Standardization of Medical and Diagnostic Tests (ÖQUASTA), Hörlgasse 18/5, 1090, Vienna, Austria.

Wiener Klinische Wochenschrift +

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April 23, 2024

View abstract on PubMed

Summary

Following the COVID-19 pandemic, SARS-CoV-2 testing decreased, impacting external quality assessment (EQA) performance. Post-pandemic EQAs revealed lower true positive ratios, especially in nonmedical labs and manual test systems for low-concentration samples.

Area Of Science

Clinical diagnostics
Infectious disease surveillance
Laboratory quality assurance

Background

External quality assessment (EQA) schemes are crucial for evaluating laboratory performance and analytical systems.
During pandemics like COVID-19, EQAs assess test reliability and inform testing strategies.
A significant decrease in SARS-CoV-2 testing occurred in Austria post-pandemic, prompting an analysis of EQA participation and performance.

Purpose Of The Study

To investigate the impact of reduced SARS-CoV-2 testing frequency on participation and performance in external quality assessment (EQA) schemes.
To compare post-pandemic EQA results with data from the pandemic era.
To identify specific laboratory types and test system formats associated with performance variations in SARS-CoV-2 detection.

Main Methods

Identical samples were distributed to participating laboratories for SARS-CoV-2 virus detection EQA.
Results were evaluated based on agreement with defined targets, analyzed as a single EQA round.
Performance was assessed using true positive ratios, with subgroup analysis by laboratory type (medical/nonmedical) and test system format (automated/manual).

Main Results

The false negative ratio in the first post-pandemic EQA was 4.3%, compared to 5.7% during the pandemic.
Medical laboratories (0.4% false negative) and automated systems (1.2% false negative) outperformed nonmedical labs (22.8%) and manual systems (16.7%).
Lower true positive ratios post-pandemic were linked to specific lab types and assay formats, particularly with low-concentration samples.

Conclusions

Post-pandemic SARS-CoV-2 EQA showed a lower true positive ratio compared to the pandemic mean, similar to early pandemic rounds.
Laboratory type and assay format significantly influenced performance, especially for low-concentration samples.
Continued EQAs are essential to maintain epidemiological data quality despite decreased vigilance post-pandemic.

Keywords:

COVID-19 Diagnostics Molecular NAT PCR Virus genome detection