SCAN Study Frequently Asked Questions

for RADAR SCAN Participants Past, Present, and Future

What is COVID-19?

COVID-19 is the infection caused by a virus called SARS-CoV-2. SARS stands for severe acute respiratory syndrome. SARS-CoV-2 is related to the first SARS virus that spread in 2003. SARS-CoV-2 was first described in China in late 2019 where it was associated with severe shortness of breath. During the months of January through March 2020, SARS-CoV-2 virus spread throughout the world, including spreading here in Chicago. SARS-CoV-2 is a coronavirus, which means it includes a small amount of RNA nucleic acid surrounded by proteins, which resemble spikes on the surface of the virus. These spikes help the virus enter a person’s cells and cause infection. We know that only a fraction of people become very sick from SARS-CoV-2, and many people experience much milder symptoms. After infection, we can measure antibodies developing in the blood usually several weeks after the infection. Antibodies are naturally produced proteins by the body to help fight infection, and measuring antibodies in the blood is a sign the body has had a viral infection. We are measuring how many people in the RADAR study have antibodies to SARS-CoV-2.

What is the purpose of this study?

The purpose of this study is to understand the effect of COVID-19 on RADAR participants and to measure how many people in the RADAR study have antibodies to SARS-CoV-2. The presence of antibodies in the blood indicates a prior infection. Researchers have not yet confirmed whether the presence of SARS-CoV-2 antibodies in a person’s blood means they are fully protected from COVID-19. Based on what is known about similar viruses, this protection is possible; however, more research is needed. In fact, that is one research question this study may help answer.

What will I be doing in this study?
  • If you agree to participate, you will complete a short online survey (~20 minutes) with questions on topics such as your experience of COVID-19 symptoms, testing, and behaviors to prevent infection. We will also ask you to provide your address, answer basic health and home questions, and risk factors for COVID-19.
  • During the survey we will provide you the option whether you would like us to be able to contact you to invite you to participate in future COVID-19 research over the next 5 years. You will also be given information about how to tell your friends and family about the study.
  • We will mail you a kit with instructions and materials for you to prick your finger and place drops of blood on a paper card. You will then return the sample to us in the mail. It is safe to ship these kits in the mail. The blood samples are dried and you will place them in a sealed pouch. There is no risk of SARS-CoV-2 transmission to the mail carrier or others who handle the package from the blood specimen in the package.
  • Samples will then be analyzed for SARS-CoV-2 antibodies in the collaborating Northwestern University laboratories. We will return your results using a website with encryption and multiple forms of authentication. This system protects your identity, so that who you are and where you live cannot be linked to your test result.
  • If you agree, we may invite you to participate in future COVID-19 research over the next 5 years. Examples of this research might include repeating this test or others, further questionnaires, and/or checking if you later received a COVID-19 diagnosis.
How do I use the test kit?

How long will I participate in the study?

You will be given the option to allow us to contact you to invite you to participate in future COVID-19 research over the next 5 years. Reasons for repeated testing in this research study are to learn how long antibodies last in the body (among those who had antibodies detected in the initial test), whether you now developed antibodies (among those who did not have antibodies at the initial test), whether you experienced symptoms, and to see if the virus spread is continuing to spread.

How long will it take for me to get my test results?

We are hoping to provide information back to participants within 2-4 weeks of receiving your sample in the mail.  However, depending on many factors, including COVID-19 itself, this timeline could be delayed.  We will place information on the website if we are experience general delays in returning results.

Are there any benefits to participating in this study?

There are no direct benefits to you of participating in this study. You will be helping to understand the spread of COVID-19 and the development of antibodies that may provide immunity.

Are there any risks to participating in this study?

The primary risks of participation are discomfort or minimal pain from the finger prick blood draw.  At this time, you should understand that we do not know the full meaning of antibodies to the COVID-19 virus.  Some of these antibodies may provide immunity or protection against future infection, but that is not completely known at this time.  This is one of the reasons we may wish to contact you in the future to learn about your health and wellbeing in the coming months.

Is my personal information kept private?

Your personal information will only be known by members of the study team responsible for mailing you the kit and making your results available to you over the internet. Study team members performing the test and analyzing the results are not aware of your name, since your blood spot will be labeled with a code and not your name. Efforts will be made to limit the use and disclosure of your personal information, including research study records, to people who have a need to review this information. We cannot promise complete secrecy. Organizations that may inspect and copy your information include the IRB and other representatives of this institution.

Who can I talk to?

You can text or call us at 773-417-9772, or email us at

I’m interested in finding out more information about the antibody test being used.

The antibody test used for this study is the COVID-19 Elisa IgG Antibody Test. It has a sensitivity of 92.5% and a specificity of 100%. It was adapted from a quantitative ELISA granted Emergency Use Authorization from the FDA. This ELISA measures SARS-CoV-2 antibodies in serum. It was recently used to detect a higher than expected seroprevalence for antibodies to SARS-CoV-2 among health care workers and patients. For more information, please refer to the following articles:  Article 1 and Article 2.

Is this a vaccine or drug trial?

Please note that this is not a vaccine trial and you will not receive any experimental drugs.

What is the rate of false positives for this antibody test?

The SCAN test is very specific for SARS-CoV-2, the virus that causes COVID-19. 100% of blood samples from before 2018 are negative in this test. This means 100% of the blood samples before COVID-19 show no antibody in the SCAN test.

Why would someone in my household test negative while I tested positive?

Studies show there is a high household spread of COVID-19. Our study suggests that if one person in the house had COVID-19, about 70% of household members will show antibodies to COVID-19. But, not every member of a household will become infected with COVID-19. Not every person will become positive in a household.

I tested positive for COVID antibodies in RADAR SCAN, but I recently received a negative test result using another antibody test. Why?

The test used in RADAR SCAN is very sensitive to pick up even low levels of antibodies to COVID-19. We think that this test detects lower amounts of antibodies than many other tests. This explains why you may be positive on the RADAR SCAN study and negative on other commercial tests.

I sent in my kit weeks ago but still haven’t received my results.

Please note that due to delays with USPS, we expect to receive your dried blood spot card 2 – 4 weeks after you mail it to back us. We will send your results to you shortly afterwards. You will receive an automated email with a secure link to your results when they are ready.