The Coris BioConcept COVID 19 Ag Respi-Strip, a field experience feedback

This communication described how the Coris BioConcept COVID-19 Ag Respi-Strip test (Coris-Ag) was implemented in the workflow of our clinical microbiology laboratory for COVID-19 diagnosis. The diagnostic performance statistics (sensitivity, specificity) of the Coris-Ag were evaluated against a gold standard, the RealStar SARS-CoV-2 RT-PCR kit 1.0. Additionally, the effect of reading the Coris-Ag results at 30 min was compared to reading at 15 min. The Coris-Ag was performed on a total of 294 patients during two periods; 158 patients were tested during period 1 at the peak of the pandemic (April 6th to April 10th 2020) which returned a positivity rate of 17.1 %, and 136 patients during period 2 (April 12th to April 16th 2020) which returned a positivity rate of 11 %. Compared to the RT-PCR, the 15-minute Coris-Ag readings resulted in a sensitivity of 59.3 % with a 100 % specificity for the period 1 patients (n = 158) while the sensitivity decreased to 20 % for the period 2 patients (n = 136). The overall sensitivity was 38.1 % for both periods (n = 294). The corresponding 30-minute readings produced a 7 % increase in sensitivity with a specificity of 100 % (n = 294). The sensitivity of the strip test (15 min reading) for high viral loads (Ct <25) was 84.6 %.

Automated summary

This study described the implementation of the Coris BioConcept COVID-19 Ag Respi-Strip test in a clinical microbiology laboratory for COVID-19 diagnosis, with performance evaluation against a RT-PCR kit as the gold standard. The 30-minute readings slightly improved the sensitivity compared to the 15-minute readings, but the overall sensitivity was still relatively low.