Diagnostic accuracy of the ultrasensitive S-PLEX SARS-CoV-2 N electrochemiluminescence immunoassay

We carried out a digital search in the two scientific databases Medline (PubMed interface) and Scopus, using the following keywords: “S-PLEX” AND “COVID-19” OR “SARS-CoV-2”, without no language or date (i.e., up to February 17, 2022) restrictions. Four studies (totalling 657 clinical samples) were included in our analysis. The cumulative diagnostic sensitivity was 0.87 (95%CI, 0.83-0.90), the specificity 0.92 (95%CI, 0.89-0.95), the area under the curve (AUC) 0.955 (95%CI, 0.944-0.967), whilst the accuracy was 89.5% (95%CI, 86.9-91.7%). Similar results were obtained when our analysis was restricted to three studies which evaluated SARS-CoV-2 in NPS or saliva, in that the sensitivity was 0.86 (95%CI, 0.81-0.89), the specificity 0.92 (95%CI, 0.88-0.95), the AUC 0.950 (95%CI, 0.934-0.966) and the accuracy 88.7% (85.7-91.3%), respectively. The results of our critical literature review and pooled analysis confirm that the ultrasensitive S-PLEX SARS-CoV-2 N electrochemiluminescence immunoassay displays excellent performance for detecting SARS-CoV-2 N antigen in a vast array of clinical specimens (NPS, saliva and even plasma), exhibiting a cumulative diagnostic sensitivity as high as 87%, which would make it one of the most sensitive SARS-CoV-2 antigen tests currently available in the market.