- Recovered SARS patients provide blood, urine, and stool samples and have a mouth and throat swab and nose aspiration to see if the SARS virus is present. For the nasal aspiration, salt water is put in the nose and then suctioned out. Usually, these tests are done only once. If virus is detected, however, the nose washing, throat swabs and blood tests are repeated once a week until no virus is detected for 3 weeks in a row.