Clinical Report: Diagnostic Efficacy of Universal SARS-CoV-2 Testing in Asymptomatic Patients

Overview

This study evaluated the diagnostic yield and clinical impact of systematic SARS-CoV-2 screening in asymptomatic patients admitted to a tertiary hospital over 89 weeks. Findings highlight correlations between test positivity, community incidence, and wastewater viral loads, while also addressing the consequences of false-positive results on patient management.

Background

Healthcare settings are high-risk environments for SARS-CoV-2 transmission, with secondary attack rates in shared hospital rooms comparable to households. Universal testing of asymptomatic patients is recommended during high community incidence to mitigate nosocomial spread, but systematic screening has potential drawbacks including delays in care and false-positive results. This study investigates the diagnostic efficacy of universal SARS-CoV-2 screening in asymptomatic patients and its association with community infection metrics and patient outcomes.

Data Highlights

Key Findings

• Systematic screening detected SARS-CoV-2 infections in asymptomatic patients correlating with community 7-day incidence and wastewater viral loads.
• False-positive results were more frequent in low-prevalence settings and were associated with unnecessary delays in medical interventions and isolation measures.
• Patients with equivocal initial test results required confirmatory testing to distinguish true from false positives, impacting patient management.
• Universal screening helped identify infections early, potentially reducing nosocomial transmission in a high-risk hospital environment.
• Screening intervals and testing strategies were adapted over time based on epidemiological data to optimize resource use and clinical benefit.

Clinical Implications

Universal SARS-CoV-2 screening in asymptomatic hospital admissions can aid early detection and reduce in-hospital transmission during periods of high community incidence. However, clinicians should be aware of the potential for false-positive results, especially in low-prevalence settings, which may lead to delays in care and unnecessary isolation. Confirmatory testing protocols are essential to minimize these adverse effects and optimize patient management.

Conclusion

Systematic SARS-CoV-2 screening of asymptomatic patients in hospital settings demonstrates diagnostic value aligned with community infection trends but requires careful interpretation of equivocal and false-positive results to avoid negative clinical consequences.

References

1. European Society of Clinical Microbiology and Infectious Diseases 2021 -- Recommendations on universal testing
2. Open Data Basel-Stadt 2021 -- Regional epidemiology and wastewater viral load data