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What types of tests are available for COVID-19? And what’s the difference?

There are two types of tests available for COVID-19:

  • Diagnostic tests check whether you have an infection and if it is contagious. These tests are done by spitting into a cup or having a swab inserted into your nose or throat. There are two kinds of diagnostic tests: laboratory-based tests and point-of-care tests (also called rapid tests). Laboratory tests take longer but are more accurate.
  • Antibody or serology tests measure the presence of antibodies in the blood. These tests require blood to be drawn and show if you had a previous infection. They cannot tell if you have an active infection at the time of the test.


What are the two types of diagnostic tests?

1. Molecular tests: PCR (polymerase chain reaction) and LAMP tests

  • Done in a laboratory
  • Thought to be the most accurate option
  • Generally take longer. This is because they take a few hours to complete after being sent to the lab. 

2. Antigen tests

  • Most common type of rapid or point-of-care tests
  • Most often much faster
  • Most often cheaper than PCR or LAMP tests
  • Tend to be less accurate when the result is negative
    • This means you may get a “false negative” result. For example, your rapid test may show you are negative for an active COVID-19 infection. But a PCR test may show that you are actually positive. Sometimes testing more often can make up for some of these issues.

Talk to your doctor before using a rapid antigen test. Ask them:

  • If it's the right test for you.
  • What the results might mean.


What are the differences between the two diagnostic tests?

All tests may vary in their accuracy. This can depend on:

  • How specimens are collected and handled,
  • Time between exposure and testing,
  • How much virus is present in the test sample,
  • The manufacturer of the test kit, and
  • The lab that is analyzing the test sample.


I’ve heard there are concerns about antibody tests. What are those concerns?

An antibody or serology test generally cannot show if there is a current infection. This is because it can take 1 to 3 weeks after infection to make antibodies. This test is not suitable for the diagnosis of a current infection.

Also, it hasn’t been determined if having antibodies to the virus or a positive test result can protect someone from getting infected with the virus again. If there is protection, it is also not known how long it might last or if someone with antibodies could still be contagious. 

Blue Shield will not cover antibody tests unless ordered by a healthcare provider licensed to order COVID-19 tests (and for the rare case in which it is needed to help make a diagnosis). Also, members will likely have to pay out-of-pocket for these types of tests since they do not fall under the diagnostic tests covered at no cost to the member. 


Who can get tested for COVID-19?

Everyone can get tested. Learn more about when and how tests are covered by Blue Shield.


When should I get tested?

Timing for testing is important. The incubation period for COVID-19 is around 5 to 7 days. But it can be up to 14 days. 

If you have symptoms, it is advised that you take a test 3 days after symptoms develop. If you have been exposed to COVID-19 but have no symptoms, it is advised that you take a test 4 - 8 days after exposure. 

Testing too early or too late is likely to result in a negative test even if you have been infected. Your healthcare provider can help determine when you should be tested.

A symptom flowchart to determine whether or not you should get tested for COVID-19 in English


If I test negative, does that mean I don't have COVID-19?

If your diagnostic test for COVID-19 is negative, you could still have COVID-19. This can happen if the test was taken too early or too late in the infection. It can also depend on the type of test you took. The negative test result just means that you probably did not have COVID-19 at the time of your test. Also, sometimes the test can be wrong. That does not mean you will not get sick or that you are not contagious. You could also be exposed to COVID-19 and get infected after the test. Everyone needs to take precautions even if they have had a negative test.


What do I do if I test positive?

Speak with your healthcare provider about the next steps for care. Read more about getting care.


Where can I get a COVID-19 test?

Blue Shield recommends that you visit an in-network testing site whether you have a healthcare provider order or not. However, diagnostic testing performed by out-of-network health care providers is also covered at no cost to members during the public health emergency.

You have a few options for where to get a test:


Should I still get tested for COVID-19 even after I’ve been fully vaccinated?

Yes. If you have symptoms of COVID-19, you should get tested. This is true even after being vaccinated. Tests for COVID-19 work the same in vaccinated people as they do in unvaccinated people.

As more is learned about the vaccine, this guidance may change.