An Excalibur COVID-19 test is great for workplaces, care homes, healthcare environments are more who require a fast, accurate coronavirus test. This test requires a single nostril swab test to collect a sample. This will then be processed using a fluid called extraction buffer. The sample is placed in an extraction tube with approximately 4ml of the buffer. After 1 minute, the sample should be placed on the antigen card. Wait 15 minutes and read the results for a negative or positive test for COVID-19.