Primary Care in Rochester and Kasson

COVID-19 Testing: What you need to know

7/9/2020 by Denise Dupras, MD


Understanding what COVID-19 testing is and who needs to be tested is difficult. There are two types of tests to assist your provider in determining the care you need.

Swab test (diagnostic test) – Do you have it now?

The swab test is used to diagnose infection in patients who have symptoms suggestive of COVID-19 (fever, chills, body aches, trouble breathing, etc.). It is obtained using a swab to obtain a sample from the back of your nose and uses PCR (polymerase chain reaction) technology, which is a sensitive method to detect the virus.

If the test is positive, it means you have the virus and will need to self-quarantine for a period of time, usually 14 days. People with whom you have had close contact in the prior two weeks should also be tested.

Blood test (antibody test or serology test) – Did you have it?

The second test is the antibody test, which is obtained from a blood sample. The viral infection causes your body’s immune system to activate and produce antibodies to help fight the infection. If the antibody test is positive, it suggests you have had an infection with COVID-19. What isn’t known is how long the antibodies remain and if they are protective against re-infection with COVID-19.

There are currently studies using the serum (a component of blood) from patients who have recovered (convalescent serum) to treat patients with severe COVID-19 infection. The antibodies in the recovered patients’ serum can help ill patients recover more quickly. If your antibody (serology) test shows that you have COVID-19 antibodies, you may be eligible to donate serum for these studies.

Like most tests, neither the diagnostic swab nor antibody test is perfect, which means it can be wrong sometimes, necessitating repeat testing in some situations.

Preventive measures to protect yourself and others

  • Wear a mask whenever you leave your home
  • Wash your hands often
  • Stay home when you're sick
  • Maintain a social distance
  • Call your provider if you have symptoms and need testing
  • Follow state, local, and employer guidelines

Mayo Clinic has adopted a number of procedures to prevent the spread of COVID-19, including requiring both staff and patients to wear masks, screening for all patients that come to outpatient appointments, and testing for COVID-19 using both the diagnostic and antibody tests before procedures and surgeries.

If you have COVID-19 symptoms or you've been in contact with someone diagnosed with COVID-19, contact your care team for guidance.

Dr. Denise Dupras is a general internist in Primary Care in Rochester's Division of Community Internal Medicine (CIM). She completed her MD-PhD at Mayo Medical School and her residency in Internal Medicine at Mayo Clinic in Rochester. Her interests include medical education and evidence-based medicine.