Background: SARS-CoV-2 antigen rapid diagnostic tests (Ag-RDTs) are increasingly being inte-grated in testing strategies around the world. Studies of the Ag-RDTs have shown variable performance. In this systematic review and meta-analysis, we assessed the clinical accuracy (sensi-tivity and specificity) of commercially available Ag-RDTs.
Methods: We registered the review on PROSPERO (Registration number: CRD42020225140). We systematically searched multiple databases (PubMed, Web of Science Core Collection, medRvix and bioRvix, FINDdx) for publications up until December 11th, 2020. Descriptive analyses of all studies were performed and when more than four studies were avail-able, a random-effects meta-analysis was used to estimate pooled sensitivity and specificity in comparison to reverse transcriptase polymerase chain reaction testing. We assessed heterogeneity by subgroup analyses ((1) performed conform with manufacturers instructions for use (IFU) or not, (2) symptomatic vs. asymptomatic, (3) duration of symptoms less than seven days vs. more than seven days, (4) Ct-value <25 vs. <30 vs. >30, (5) by sample type)) and with meta-regression. We assessed study quality and risk of bias using the QUADAS 2 assessment tool.
Results: From a total of 11,715 articles, we extracted 98 analytical and clinical data sets. 74 clinical accuracy data sets were evaluated that included 31,202 samples. Across all meta-analyzed samples, the pooled Ag-RDT sensitivity was 73.8% (CI 68.6 to 78.5). If analysis was re-stricted to studies that followed the Ag-RDT manufacturers instructions using fresh upper res-piratory swab samples, the sensitivity increased to 79.1% (95%CI 75.0 to 82.8). The SD Biosensor Standard Q and Abbott Panbio showed the highest sensitivity with 81.7% and 72.7%, respectively. The best Ag-RDT performance was found with nasopharyngeal sampling (77.3%, CI 72.0 to 81.9) in comparison to other sample types (e.g., anterior nasal or mid turbinate 63.5%, CI 49.5 to 75.5). Testing in the first week from symptom onset resulted in higher sensitivity (87.5%, CI 86.0 to 89.1) compared to testing after one week (64.1%, CI 54.4 to 73.8). The tests performed markedly better on samples with lower Ct-values, i.e., <30 (87.9%, CI 86.7 to 88.8), in comparison to those with Ct >30 (47.8%, CI 41.1 to 54.5). Bias concerns were raised across all data sets, and financial support from the manufacturer was reported in 28.2% of data sets.
Conclusion: As Ag-RDTs detect most cases within the first week of symptom onset and those with high viral load, they can have high utility for screening purposes in the early phase of disease, and thus can be a valuable tool to fight the spread of SARS-CoV-2. Standardization of con-duct and reporting of clinical accuracy studies would improve comparability and use of data.
