Sofia 2

"SARS-CoV-2 antigen test advantages include low cost, wide availability and rapid turnaround time, making them important screening tests. The performance of antigen tests may vary with patient characteristics, so performance characteristics should be accounted for when designing testing strategies and interpreting results."

"These findings suggest that antigen testing alone, even when mandated and directly observed, may not be sufficient as an intervention to prevent SARS-CoV-2 outbreaks in congregate settings, and they highlight the importance of vaccination to prevent SARS-CoV-2 outbreak in congregate settings."

"Antigen testing has high specificity with a short turnaround time but is not as sensitive as RT-PCR. Daily antigen testing or RT-PCR testing two to three times a week is similar. There are benefits and drawbacks to each testing approach."

"Compared to antigen-based lateral flow assays [BD Veritor™ Plus System, Sofia® Strep A+ Fluorescent Immunoassay, and Sekisui Diagnostic OSOM® Strep A test for GAS detection], the molecular ID Now Strep A 2 assay demonstrated a lower LoD, which translates into higher sensitivity. In a clinical setting, this could enable detection of samples with a lower bacterial load that could be missed by low-sensitivity LFAs."

"Assay performance can be modeled as dependent on viral load, fit using laboratory bench study results, and adjusted to account for direct-specimen testing. When using nasopharyngeal specimens, direct testing on Abbott ID NOW and VTM testing on DiaSorin Simplexa have similar performance."

"In conclusion, the present study compares for the first time four S. pneumoniae UATs with automatic interpretation using their respective readers on defined clinical samples [BinaxNOW S. pneumoniae Antigen Card (Abbott, Chicago, IL, USA), ImmuView S. pneumoniae and Legionella (SSI Diagnostica, Hillerød, Denmark), STANDARD F S. pneumoniae Ag FIA (SD Biosensor, Gyeonggi, South Korea), and Sofia S. pneumoniae FIA (Quidel Corporation, San Diego, CA, USA)]. The four assays performed similarly and are largely in agreement for the detection of S. pneumoniae urinary antigen. The use of a reader, availability of barcode scanning, and automated sample incubation brings increased flexibility, ease of use, and standardization in performing UATs in the clinical routine, thus improving patient diagnosis through increased efficiency and decreased probability of errors."

The Quidel Sofia SARS FIA antigen test shows an 82.0% positive agreement with the Hologic Aptima SARS-CoV-2 TMA molecular test when used within five days of symptom onset. While its sensitivity drops to 54.5% after this period, the Quidel Sofia effectively identifies 87.2% of likely infectious cases. Despite lower sensitivity than the Hologic Aptima, its speed and high specificity make it a valuable tool for rapid COVID-19 screening in high-prevalence areas.

"In conclusion, we compared four Legionella UATs with automatic interpretation of test results using defined clinical samples and found that they performed similarly in detection of Legionella urinary antigen [BinaxNOW Legionella Antigen Card (Abbott), ImmuView S. pneumoniae and Legionella (SSI Diagnostica), STANDARD F Legionella Ag FIA (SD Biosensor), and Sofia Legionella FIA (Quidel)]. Results between automated and visual interpretation of ICT-based UATs were mostly consistent with each other. The use of an automated reader also brings increased flexibility and convenience in performing urinary antigen assays in the clinical routine."

"The high specificity of the rapid antigen tests [STANDARD™ Q COVID-19 Ag, PCL COVID-19 Ag Rapid FIA, BIOCREDIT COVID-19 Ag, and Sofia SARS-CoV-2 antigen FIA] and other parameters like simplicity, rapidity, and affordability suggest that antigen tests are likely to be helpful if integrated and interpreted appropriately in stepwise diagnostic algorithms. Given the low sensitivity of 64.0-69.8% of the antigen tests [compared to real-time reverse transcription PCR], we recommend that clinically relevant negative results undergo further testing to confirm or exclude a COVID-19 diagnosis."

"The high performance of the evaluated FIAs [SOFIA SARS Antigen FIA (Quidel Corporation, San Diego, CA, USA) and STANDARD F COVID-19 Ag FIA (SD Biosensor Inc., Gyeonggi-do, Republic of Korea)] indicates a potential use as rapid and PCR-independent tools for COVID-19 diagnosis in early stages of infection. The excellent sensitivity to detect cases with viral loads above ~106 copies/mL (Ct values less than or equal to 25), the estimated threshold of contagiousness, suggests that the assays might serve to rapidly identify infective individuals."

"The ID NOW, Sofia, and other emerging point-of-care tests should be used only after careful consideration of testing workflow, biosafety risk mitigations, and appropriate staff training."

The Veritor test met EUA criteria with a positive percent agreement of eighty percent or greater and AUC values of zero point nine zero or higher within zero to six days of symptom onset. Outperforming the Sofia 2 in positive detections, this fifteen-minute nasal swab test offers a fast, safe, and effective diagnostic solution compared to labor-intensive methods. Its performance in clinically relevant populations makes it an essential alternative to PCR in decentralized settings where rapid turnaround is critical for patient management.

The Immunocatch Legionella assay demonstrates excellent diagnostic performance for detecting L. pneumophila (serogroup 1) in urine, showing high sensitivity (98.5%) and specificity (99.4%) compared to the Sofia FIA and BinaxNOW tests. Despite relying on visual reading rather than automation, the test is a reliable, cost-effective, and user-friendly tool that streamlines laboratory workflows without requiring specialized equipment.

"Overall, sample testing throughout the experiments was comparable between the manual and automated methods. Testing costs were lower for the manual method when tests and machines are considered. However, the automated method should require fewer laboratory personnel, which is a significant cost savings. When all factors are considered, the overall costs are fairly comparable and both methods are capable of performing tasks as needed."

This study on K-12 students in Wisconsin (2015–2020) shows that the Sofia® RIDT is highly specific (97.2%) but only moderately sensitive (76.1%). Test accuracy depends heavily on timing and symptoms: sensitivity peaks just one day after symptom onset and is significantly higher in children with a runny nose or nasal congestion. In contrast, older age, the presence of other viruses, or waiting several days to test increases the risk of false negatives. Consequently, while these tests are effective for quick community screening, negative results should be interpreted cautiously, especially when typical nasal symptoms are absent or testing is delayed.

"Quidel Sofia SARS Ag FIA meets the minimum performance criteria of accuracy for SARS-CoV-2 antigenic testing, thus combining satisfactory diagnostic performance with the advantages of being potentially used as a portable device."

"Surveillance for significant respiratory pathogens can be based on rapid antigen testing within SHOs, is highly comparable with larger scale surveillance programs, and demonstrates either advanced (FluA) or concurrent detections (SC2). Performance of similar programs are needed in other geographical areas and for other pathogens."

"Clinical and laboratory factors may affect RIDT sensitivity. Identifying potential factors during point-of-care testing could aid clinicians in appropriately interpreting negative influenza RIDT results."

"This antigen test for SARS-CoV-2 was of reasonable clinical utility in a low prevalence environment but concerns about the actual prevalence of COVID-19 and the ramifications of false negatives limited its use. Difficulty recruiting subjects and the resultant delay in the results made it impossible to implement this antigen testing in primary care practices, but it is hoped that these data will contribute to the accumulation of evidence about diagnostic testing for COVID-19."

"Sofia-Ag-RDT is a lower-cost option for the rapid diagnosis of SARS-CoV-2 in symptomatic children. However, in instances where Sofia-Ag-RDT has inadequate performance, such as in asymptomatic children or in symptomatic children who test negative despite clinical suspicion of COVID-19, reflex or confirmation RT-PCR testing should be considered."

"Our results show that the Sofia test meets the standards for diagnostic tests according to the criteria of the World Health Organization, as they show high sensitivity and specificity, and perhaps most importantly, a high negative predictive value (> 95%)."

"Using highly specific rapid COVID-19 tests in COVID-19 suspects at German ER, despite of their sub-optimal sensitivity, may significantly reduce hospital expenditure."

"Using highly sensitive and specific real-time influenza tests in ILI patients at German ER might significantly reduce hospital expenditures."