Validation of the STANDARD Q COVID-19 antigen test in Vojvodina, Serbia

Abstract

Background Since COVID-19 pandemic is a global crisis, tests with high sensitivity and specificity are crucial for the identification and management of COVID-19 patients. There is an urgent need for low-cost rapid antigen COVID-19 test with a good diagnostic performance. Although various antigen rapid detection tests are widely available, strong evidence of their usefulness in clinical practice are still limited. Therefore, our aim was to evaluate clinical performance of STANDARD Q COVID-19 Ag Test (SD Biosensor, Gyeonggi-do, South Korea). Methods The performance of the STANDARD Q COVID-19 Ag Test for the detection of SARS-CoV-2 antigen was evaluated in comparison to RT-qPCR results in 120 symptomatic patients (median age 49, IQR 36–70) who presented to health care facility in Novi Sad, Vojvodina, Serbia. Results Twenty five out of 120 samples have been tested positive using STANDARD Q COVID-19 Ag Test, and all of them were also positive on RT-qPCR. Overall, the STANDARD Q COVID-19 Ag Test showed sensitivity of 58.1% (95% CI 42.1–73.0) but it was higher in the early days of disease, when the highest viral loads were detected. During the first five days after the symptom onset, the sensitivity ranged from 66.7% to 100% and the pooled accuracy and Kappa values were high (0.92 and 0.852). Conclusions A strong agreement between performance of STANDARD Q COVID-19 Ag Test and RT-qPCR was observed during the first five days of illness, suggesting that this rapid antigenic test can be very useful for COVID-19 diagnosis in the early phase of disease.

Accuracy of novel antigen rapid diagnostics for SARS-CoV-2: A living systematic review and meta-analysis

“…Median Ct values differed in symptomatic and asymptomatic patients. For those studies where it was possible to extract a median Ct value, it ranged from 20.5 to 27.0 in symptomatic patients [170,207,226,258,271,272] and from 27.2 to 30.5 in asymptomatic patients [170,201,258].…”

Seroprevalence of antibodies against SARS-CoV-2 virus in Northern Serbia (Vojvodina): A four consecutive sentinel population-based survey study

“…Throughout the COVID-19 outbreak in Vojvodina, a RT-PCR test has been permanently available for laboratory confirmation of infection. An immunochromatographic qualitative assay for detection of both IgG and IgM anti-SARS-CoV-2 antibodies was also used in parallel with RT-PCR [ 9 , 10 ]. As a result of implementation of different testing criteria in our country during the course of epidemic, it is likely that many asymptomatic and mild SARS-CoV-2 infections were underreported, similar to situations observed in other regions [ 1 – 7 ].…”

SARS-CoV-2, CT-Values, and Infectivity—Conclusions to Be Drawn from Side Observations

“…These data do not allow any general estimation of sensitivity or specificity of antigen tests per se, but it clearly shows that the use of RATs could lead to a profound percentage of undetected SARS-CoV-2 infections, especially in asymptomatic individuals. This is of relevance as it is already known that asymptomatic patients can also spread the virus and SARS-CoV-2 infections are not reliably identified by rapid antigen testing in these individuals [ 5 , 6 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 ]. Taking into account that it is postulated that there are between 2.6- and 8-fold more SARS-CoV-2 infections than those identified by testing [ 40 , 41 ], either because they are asymptomatic or because their symptoms are too mild to initiate testing algorithms, false negative antigen tests could boost an unnoticed and uncontrolled viral spread due to an unjustified sense of security.…”