# Evaluation of the Analytical Performance of the STANDARD Q COVID‐19 Antigenic Test in Suspected COVID‐19 Cases in Bobo‐Dioulasso, Burkina Faso

## TL;DR

This study evaluated the accuracy of a rapid antigen test for detecting COVID-19 in Burkina Faso, finding it highly specific but not very sensitive compared to PCR testing.

## Contribution

The study provides a performance evaluation of the STANDARD Q antigen test in a resource-limited setting, highlighting its limitations in sensitivity.

## Key findings

- The STANDARD Q antigen test showed high specificity (98.65%) but low sensitivity (26.32%) when compared to RT-PCR.
- The test's sensitivity improved to 41.18% for specimens with cycle threshold (Ct) values below 20.
- The test had minimal agreement (Cohen’s kappa of 0.36) with RT-PCR results.

## Abstract

The use of alternative technique such as rapid antigen diagnostic tests (Ag‐RDTs) is needed in countries with limited resources for fast tracking of COVID‐19 cases. This study evaluated the performance of the STANDARD Q COVID‐19 antigen test compared with reverse transcriptase polymerase chain reaction (RT‐PCR) among suspected COVID‐19 cases using nasopharyngeal and/or oropharyngeal swabs in Bobo‐Dioulasso, Burkina Faso.

A cross‐sectional study was conducted from April to September 2021. The respiratory secretions of suspected COVID‐19 cases were collected at the Virology Laboratory of Sourô Sanou University Hospital in Bobo‐Dioulasso. The respiratory secretions consisted of nasopharyngeal or combined nasopharyngeal/oropharyngeal swabs. Each sample was analyzed using the STANDARD Q COVID‐19 Ag test and RT‐PCR on the Abbott m2000 RealTime system.

A total of 152 respiratory specimens were collected from suspected COVID‐19 cases and processed in this study. The sensitivity and specificity of the Ag‐RDT were 26.32% (9.15–57.20) and 98.65% (92.7–99.9), respectively, in the suspected cases with nasopharyngeal swabs from suspected cases, while a sensitivity of 25.0% (3.2–65.1) and a specificity of 98.65% (92.7–99.9) were shown with combined nasopharyngeal/oropharyngeal swabs from suspected cases. The accuracy and Cohen′s kappa of the test were 83.87% and 0.36 in suspected cases with nasopharyngeal swabs from suspected cases, while they were 83.37% and 0.32 in oropharyngeal swabs. In our study, Ag‐RDT was not sensitive on the specimens of suspected COVID‐19 cases with Ct values ≥ 20, whereas its sensitivity increased to 41.18% (18.4–67.1) on specimens with Ct < 20.

The study findings have shown that the Ag‐RDT is useful in suspected COVID‐19 cases. However, the sensitivity of the STANDARD Q COVID‐19 Ag test was low with minimal agreement in comparison to RT‐PCR on the Abbott m2000rt system.