Evaluation of antigen-based rapid detection test for the diagnosis of SARS CoV-2 in low-income countries

Abstract

Background In the context of the Covid-19 pandemic and following the increasing number of suspicious Covid-19 cases in Madagascar, Malagasy laboratories are overflowed mainly due to lack of human resource and available material restriction. The development and validation of rapid and easy-to-perform diagnostic methods are worth of interest and high priority. The aim of this prospective study was to evaluate the performances of a rapid immunochromatographic test for the detection of SARS-CoV-2 antigen, in comparison to Reverse transcription polymerase chain reaction (RT-PCR). Methods The fluorescence immunochromatographic SARS-CoV-2 antigen test StandardTM Q COVID-19 Ag Test (SD Biosensor Republic Korea) was evaluated in samples derived from patients who were examined for disease categories. Diagnostic accuracy was determined in comparison to SARS-CoV-2 RT-PCR considered as gold standard. Results A total of 200 samples were included; 94 were RT-PCR positive. Median patients’ age was 38.36 years, 63.5 % were male. Overall sensitivity and specificity of the Standard TM Q COVID-19 Ag (SD Biosensor® Republic Korea) were 62.66% and 100%, the sensitivity was significantly higher (100%) in samples with high viral loads (Ct<29). Conclusions This antigen-based immunofluorescence RDT could be the potential to become an important tool for the early diagnosis of SARS-CoV-2 particularly in situations with limited access to molecular methods particularly in rural area of Madagascar.

Evaluation of Rapid Antigen Tests Using Nasal Samples to Diagnose SARS-CoV-2 in Symptomatic Patients

“…One of the most effective ways to mitigate a viral outbreak in the absence of population-wide vaccination is the efficient detection of cases early enough to take the necessary precautions that could halt its spread to contacts and allow for the adequate management of high-risk patients. However, this is difficult to achieve in the absence of a readily available, rapid, and cost-effective test with sufficiently high specificity and sensitivity for early detection of COVID-19 infected patients in the general population (5)(6)(7)(8).…”

“…Until now, nasopharyngeal Real-Time Polymerase Chain Reaction (RT-PCR) is the gold standard diagnostic test for COVID-19 (5)(6)(7)(8). RT-PCR has multiple limitations, including delayed availability of results and the need for specialized laboratory equipment as well as specialized technicians (1,5,6,8).…”

“…Until now, nasopharyngeal Real-Time Polymerase Chain Reaction (RT-PCR) is the gold standard diagnostic test for COVID-19 (5)(6)(7)(8). RT-PCR has multiple limitations, including delayed availability of results and the need for specialized laboratory equipment as well as specialized technicians (1,5,6,8). As a result, the number of tests performed per day is restricted by these limitations, risking delaying the appropriate management of positive cases.…”

“…As a result, the number of tests performed per day is restricted by these limitations, risking delaying the appropriate management of positive cases. Therefore, other diagnostic techniques are needed to limit the virus's spread and effectively monitor the degree of COVID-19 infection in the population (1,5,6,8). Current literature explores the possibility of using point-of-care rapid antigen tests as a cost-effective and simple modality that has been used effectively with other viruses such as Influenza and respiratory syncytial virus (RSV) (9).…”

“…Current literature explores the possibility of using point-of-care rapid antigen tests as a cost-effective and simple modality that has been used effectively with other viruses such as Influenza and respiratory syncytial virus (RSV) (9). However, the studies report an overall low sensitivity and high specificity compared to RT-PCR (1,5,6,8).…”