Performance of different rapid antigen testing strategies for SARS-CoV-2: A living rapid review.

Background: Rapid antigen detection tests (RADTs) for SARS-CoV-2 testing offer several advantages over molecular tests, but there is little evidence supporting an ideal testing algorithm. We aimed to examine the diagnostic test accuracy (DTA) and the effectiveness of different RADT SARS-CoV-2 testing strategies.

Methods: Following PRISMA DTA guidance, we carried out a living rapid review and meta-analysis. Searches were conducted in Ovid MEDLINE® ALL, Embase and Cochrane CENTRAL electronic databases until February 2022. Results were visualized using forest plots and included in random-effects univariate meta-analyses, where eligible.

Results: After screening 8010 records, 18 studies were included. Only one study provided data on incidence outcomes. Seventeen studies were DTA reports with direct comparisons of RADT strategies, using RT-PCR as the reference standard. Testing settings varied, corresponding to original SARS-CoV-2 or early variants. Strategies included differences in serial testing, the individual collecting swabs and swab sample locations. Overall, specificity remained high (>98%) across strategies. Although results were heterogeneous, the sensitivity for healthcare worker-collected samples was greater than for self-collected samples. Nasal samples had comparable sensitivity when compared to paired RADTs with nasopharyngeal samples, but sensitivity was much lower for saliva samples. The limited evidence for serial testing suggested higher sensitivity if RADTs were administered every 3 days compared to less frequent testing.

Conclusions: Additional high-quality research is needed to confirm our findings; all studies were judged to be at risk of bias, with significant heterogeneity in sensitivity estimates. Evaluations of testing algorithms in real-world settings are recommended, especially for transmission and incidence outcomes.