Affinity capture magnetic hydrogel particles can be used to capture SARS-CoV-2 from the saliva of a person who is being tested for the virus. In this method the virus is concentrated before the extraction of RNA occurs. Transport medium diagnostic remnant samples that have been tested before using previous methods help show that the method correctly identifies positive samples as well as improves the likelihood of detecting the virus in samples that contain a low percentage of COVID-19 positive patients.