Cost-effectiveness analysis of different COVID-19 screening strategies based on rapid or laboratory-based SARS-CoV-2 antigen testing

We carried out in this work a cost-effective analysis of some potential diagnostic protocols inclusive of SARS-CoV-2 antigen tests. The study population consisted in a series of 294 patients. All patients underwent rapid diagnostic testing (RDT-Ag, ~30 min turnaround time; Fujirebio Espline SARS-CoV-2; Fujirebio Inc., Tokyo, Japan) for enabling fast identification of positive subjects, followed by molecular (RT-PCR, 4-6 h turnaround time;; Altona Diagnostics RealStar SARSCoV-2 RT-PCR Kit; Altona Diagnostics GmbH, Hamburg, Germany) and SARS-CoV-2 laboratory-based Ag (LAB-Ag, 45-60 min turnaround time; DiaSorin LIAISON SARS-CoV-2 Ag; DiaSorin, Saluggia, Italy) testing on the same nasopharyngeal sample. Each patient included underwent the three diagnostic tests concomitantly, incorporated in seven different diagnostic strategies (i.e., RDT-Ag alone; LAB-Ag1 alone, with manufacturer’s cutoff; LAB-Ag2 alone, with locally calculated cutoff; RT-PCR alone; RDT-Ag combined with RT-PCR in negative samples; LAB-Ag1 with manufacturer’s cutoff combined with RT-PCR in negative samples; LAB-Ag2 with locally calculated cutoff combined with RT-PCR in negative samples). The three last strategies, encompassing RT-PCR in samples testing negative with RDT-Ag or LAB-Ag(1-2) were specifically selected for achieving the maximum possible accuracy in identifying patients with SARS-CoV-2 infection (i.e., “zero-tolerance for false negatives”). The costs of the three technique for assaying each individual nasopharyngeal sample (i.e., cost per test) at the local facility were as follows: RDT-Ag: 7.50 €; LAB-Ag: 3.50 €; RT-PCR: 20.0 €; respectively. The most economic strategy was that encompassing LAB-Ag alone, followed by RDT-Ag alone. Nonetheless, the best balance between cost and diagnostic accuracy (i.e., “zero tolerance for false negatives”) was found for the strategy encompassing LAB-Ag2 combined with RT-PCR in negative samples, which was cheaper than that based on RT-PCR alone (i.e., 5509 vs. 5880 €). Interestingly, the cost of the strategy encompassing LAB-Ag1 combined with RT-PCR in negative samples was comparable to that entailing RT-PCR alone (i.e., 5989 vs. 5880 €). Higher expenditure emerged using a strategy based on RDT-Ag combined with RT-PCR in negative samples (i.e., 7145 €).