Diagnostic validation of two SARS-CoV-2 immunochromatographic tests in Slovenian and Croatian hospitals.

AIM: To diagnostically validate two point-of-care (POC) rapid antigen tests for SARS-CoV-2 by comparing their results with those of laboratory-based real-time polymerase chain reaction tests (RT-PCR). METHODS: The study enrolled 455 patients from two Slovenian and two Croatian hospitals. The NADAL COVID-19 Ag Test (Nal von Minden, Moers, Germany) and ALLTEST COVID-19 Antigen Test (Hangzhou ALLTEST Biotech Co., Ltd, Hangzhou, China) were diagnostically validated in emergency care departments of two Slovenian hospitals, while only ALLTEST COVID-19 Antigen Test was validated in two Croatian hospitals. RESULTS: The antigen test results were in very good agreement with the RT-PCR results (Cohen's Kappa between 0.747 and 0.891 for the NADAL COVID-19 and between 0.820 and 0.954 for the ALLTEST COVID-19). The NADAL COVID-19 Ag Test had the sensitivity between 66.67% and 92.31%, with a negative predictive value between 85.51% and 99.2%. The ALLTEST COVID-19 Antigen Test had the sensitivity between 81.39% and 91.11%, with a negative predictive value between 85.45% and 98.78%. CONCLUSION: The antigen tests are practical and reliable screening assays for SARS CoV-2 in emergency care departments. Both antigen tests can be used as screening tests to reduce the number of patients waiting for RT-PCR results. Even more, they can be used to quickly isolate COVID-19 patients and reduce hospital transmissions.

Use of Immunochromatographic SARS-CoV-2 Antigen Testing in Eight Long-Term Care Facilities for the Elderly.

The clinical validation of the NADAL COVID-19 antigen test (Nal von Minden, Moers, Germany) started in eight Slovenian long-term health care facilities in October 2020. The purpose of clinical validation is to implement the test into the everyday working process in long-term care (LTC) facilities and demonstrate how it can be used to mitigate the spread of the virus in these environments. The facilities compared the results of antigen tests to the results obtained using Cobas 6800 SARS-CoV-2 real-time reverse transcription polymerase chain reaction (RT-PCR) (Roche, USA). Sensitivity (86.96%, 95% CI: 66.41-97.23%) and specificity (88.24%, 95% CI: 80.35-93.77%) of the NADAL COVID-19 antigen test were good. Rapid antigen testing served well for early detection of infection and helped to prevent and control spread of the SARS Cov2 in six out of eight LTCs. Moreover, mini-outbreaks were quickly resolved in all six LTCs. Locally validated immunochromatographic SARS-CoV-2 antigen testing can be used to contain the spread of the virus in LTCs. Antigen tests also deliver accurate information very quickly if used early with a low threshold. The NADAL COVID-19 antigen test proved to be a good screening tool to detect SARS-COV-2 in LTCs.