Testing Tips: Frequently Asked Questions for Diagnostic Testing

What is diagnostic testing and how does it differ from antibody testing?

  • Diagnostic testing (also called viral testing), tells you whether or not you currently have a COVID-19 infection. This type of test is administered through a respiratory swab (usually taken from the nose) and can take anywhere from a few minutes to a few days depending on the type of diagnostic test. There are two diagnostic tests available. PCR testing usually takes longer because the respiratory sample needs to be sent out to a laboratory to be analyzed, while antigen testing may take only a few minutes to receive results. 
  • Antibody testing on the other hand, detects whether someone has been exposed to the virus in the past and has developed COVID-19-specific antibodies.
  • The table below compares the available tests. 

Diagnostic TestingDiagnostic TestingSerologic Testing

Antigen Test
PCR TestAntibody Test
Other names for this test:Rapid testDiagnostic test, viral testSerologic test
What is being tested?Whether someone currently has an active COVID-19 infection. This test detects proteins that are associated with COVID-19.Whether someone currently has an active COVID-19 infection.This test detects genetic material of COVID-19.Any developed immune response to COVID-19.
What samples are usually taken?Respiratory swab (usually inside the nose). 

Newly developed saliva tests will be increasing in availability.
Respiratory swab (usually inside the nose)A blood sample
How long does it usually take to receive results?Usually a few minutesUsually a few daysUsually a few minutes (rapid tests) or up to several days (laboratory tests)
What does a positive result mean?You currently have COVID-19.You currently have COVID-19.You have likely had the virus in the past or have been previously exposed to COVID-19.

Why is diagnostic testing important?

  • The more individuals being tested, the better picture we have of the pandemic and the effects of the virus on ourselves, on our loved ones, and on our community.
  • Testing for infection allows you to isolate yourselves from others to keep from transmitting the virus.
  • It allows public health to contact you and identify others that need to quarantine because they have been exposed. 
  • Testing can help scientists and health professionals understand: 
    • How individuals are getting sick
    • How the virus spreads, and how quickly
    • The contagiousness of sick individuals
    • How to inform treatment options
    • How to best allocate healthcare resources
    • How to keep hospitals and health facilities informed about spread within a community to ensure resources are available (e.g., enough hospital beds).
  • Testing can help public health decide:
    • What kinds of prevention measures need to be enacted.
    • Whether or not the prevention strategies in place are working.
    • Where there are clusters of transmission
    • Which vulnerable populations need more testing or more support

Should I receive a diagnostic test for COVID-19?

  • If you are showing COVID-19 symptoms, it is important to get tested. 
  • If you have had close contact with someone who recently tested positive for COVID-19, it is also a good idea to get tested. Evidence suggests that the virus test (also called diagnostic, PCR, or antigen test) is the most accurate when someone is showing symptoms. 
    • You may not know you have been exposed until a public health professional called a contact tracer contacts you. You may want to get tested after they have contacted you. It is important to answer any call that says it is from the health department in Arizona OR one of the Universities; University of Arizona, Arizona State University or Northern Arizona University. The public health departments are working together with our universities to carry out contact tracing. They work as fast as they can to call everyone that has been identified as a contact to make sure they stay home to keep us all safe. 
    • For individuals who will go on to show symptoms, on average, symptoms usually appear 5-7 days after exposure, although it may take up to 14 days. Other infected individuals may not ever show symptoms despite being contagious. For information on the differences between these types of cases, please visit this link
    • If you have been exposed to COVID-19 and are not showing symptoms, you should assume that you are positive for the virus and are contagious to others. In these cases, you may get tested 5-7 days or more after your exposure, but you should be aware that your test result may not be accurate. For information on what daily precautions to take, visit this link.
  • If you are directed to get a test by a health facility for any reason (e.g., elective surgery), or your workplace requires you get tested, it is important to get tested.

How do I get tested?

State testing procedures vary by testing facility. To find a testing facility near you, visit this link. Most of the sites found at this link require pre-registration, so make sure to complete the registration form if this is necessary. If there is no pre-registration form to fill out, make sure to call ahead to the testing site to let them know you are coming.

Does it cost money?

It depends. Some facilities may charge a fee for COVID-19 diagnostic testing, some testing sites will take insurance to cover the testing cost either fully or partially, and others may provide testing free of charge as long as the tested individual meets criteria for a test (which may vary by location). Make sure to call your chosen testing facility to confirm their cost for testing.

What should I do while I am waiting for my diagnostic test result?

I got my COVID-19 diagnostic test result, what should I do now?

  • If you received a positive diagnostic test, you currently have COVID-19. You should stay home for 10 days and avoid contact with anyone after you receive your positive result. For information on what precautions to take, visit this link. As contact tracing can take time, notify anyone you were in close contact with since three days before symptom onset.
  • If you received a negative diagnostic test, you are less likely to have COVID-19 (if you received a test 5+ days after your exposure). If you get tested too early the test may not pick up the virus so it is important to wait until the right time for testing and you may need to get tested more than once. Because 20% of people that test negative may still have the virus you should still take the daily precautions necessary to prevent a COVID-19 infection, including staying home as much as possible and wearing a mask while in public.

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