Review the latest information on visitor policies, safety procedures, vaccines and more in the COVID-19 Resource Center.

Notice of a Privacy Incident. Learn More.

Advances in Care

Should I Get a COVID-19 Test?

Your COVID-19 Testing Questions Answered

As more COVID-19 tests become available, your options for testing methods are expanding, but should you get tested just because your friends or family did?

Jeffrey Kopin, MD, chief medical officer at Northwestern Medicine Lake Forest Hospital, answers common questions about COVID-19 testing. Note that these are general guidelines for COVID-19 testing. Be sure to talk to your physician before you pursue testing to determine if you need to be tested, what type of test you should have and how to proceed after you receive your results.

Who should get tested for COVID-19?

Northwestern Medicine is following the Centers for Disease Control and Prevention (CDC) guidelines for testing. You should consider COVID-19 testing if:

  • You have symptoms of COVID-19,* which include:
    • Fever or chills
    • Cough
    • Shortness of breath or difficulty breathing
    • Fatigue
    • Muscle or body aches
    • Headache
    • New loss of taste or smell
    • Sore throat
    • Congestion or runny nose
    • Nausea or vomiting
    • Diarrhea
  • You have been in close contact with someone who has tested positive for COVID-19, which means being within 6 feet of the person for more than 15 minutes.
  • Your physician recommends you get tested, whether because of symptoms or because you need to come in for another medical procedure.
  • You are in a high-risk group and were in an area with high COVID-19 transmission or attended a gathering with more than 10 people.
  • You work or live in a long-term care facility, per the discretion of your employer or provider.

* If you have symptoms of COVID-19, call your primary care provider before going in for a COVID-19 test. If you do not have a primary care provider, you may call the Northwestern Medicine COVID-19 Hotline at 312.47.COVID for guidance.

While some testing sites do not require a referral or symptoms to test you for COVID-19, Northwestern Medicine does require a physician’s referral for all COVID-19 tests.

Where can I get tested?

If you have a physician’s referral for a COVID-19 test at Northwestern Medicine, you can discuss the location of testing with your physician. Find a list of Northwestern Medicine testing sites and details here.

If you are not planning on getting tested through Northwestern Medicine, check with your state or local health departments for more information on testing options.

What can I expect from a COVID-19 test?

Diagnostic COVID-19 tests show if you have an active COVID-19 infection. They are different from antibody or serology tests, which show if you have had a COVID-19 infection in the past.

There are two main types of diagnostic COVID-19 tests; the difference between them boils down to what’s happening behind-the-scenes when your sample is tested in a laboratory.

  1. Molecular tests look for the SARS-CoV-2 virus, which causes COVID-19, by detecting its genetic material.
  2. Antigen tests don’t look for the SARS-CoV-2 virus itself. Instead, they test for certain proteins in the virus.

COVID-19 testing methods will vary by location. Both antigen and molecular test samples are mainly collected in one of two ways:

  • During an anterior nasal swab, your provider will slowly twist a cotton swab along the inside of both of your nostrils for about 15 seconds.
  • During a deep nasal swab, your provider will insert a longer swab about 1 inch into both of your upper nasal cavities and twist it for about 15 seconds.

Some molecular tests are being conducted on saliva that is collected by spitting into a tube.

How long will it take to get my test results back?

The timing of test results depends on the location and type of test used. Antigen tests are typically faster than molecular tests.

  • Antigen test results may be available in as little as 15 minutes.
  • Molecular test results can be returned in less than 24 hours but may take up to seven days.

Which test is the most accurate?

There is not enough research yet to answer this definitively. However, a negative antigen test result may need to be confirmed with a molecular test, especially if you have COVID-19 symptoms. Molecular tests seldom need to be repeated and appear to be more accurate, as they prove the physical existence of the SARS-CoV-2 virus inside your system.

What should I do while I wait for my results?

While you wait for your results, you should self-isolate to avoid the possible spread of COVID-19.

What happens if I test positive?

If you test positive:

  • Call your physician.
  • Take steps to avoid infecting others.
  • Stay home and away from other people or pets in your home until your symptoms stop.
  • Rest and hydrate.
  • Continue to monitor your symptoms and consult your physician, especially if symptoms worsen.
  • Self-isolate for 10 days, even if you have no COVID-19 symptoms.

If your symptoms become severe, go to the nearest emergency department.

If I test positive, when can I stop self-isolation?

You can stop self-isolating 10 days after your symptoms first appeared as long as your symptoms have improved and you have not had a fever for 24 hours (without the aid of fever-reducing medication like acetaminophen). Please note that loss of taste and smell may continue for weeks or months after your other symptoms improve; this is not a reason to continue self-isolating.

If your symptoms have improved and your fever is gone, talk to your physician about resuming contact with others. Your physician may recommend getting retested to ensure that the infection has cleared.

If you do not have symptoms, your physician will likely recommend getting retested before breaking your self-isolation.

What happens if I test negative?

If you test negative, it means that you were not infected with SARS-CoV-2 at the time of the test. But, this does not mean that you are in the clear or that your risk of getting COVID-19 is gone. You still should practice physical distancing, wear a face mask and wash your hands to avoid future infection and slow the spread of the virus.

Jeffrey D. Kopin, MD
Jeffrey D. Kopin, MD
Nearest Location:
Rated 5.0
star star star star star
77 Ratings
Clinical Assistant Professor, Feinberg School of Medicine
  • Primary Specialty Internal Medicine
Does Not Schedule or Accept New Patients
View Profile