FAQS for COVID-19 home antibody blood collection study

We want to understand how many of our twins across the UK currently have antibodies to fight off a COVID-19 infection. Your blood sample will be tested for the presence of antibodies against COVID-19. This will help us understand how antibody status may change in the months following infection and/or vaccination.

You can find out more about this study in the volunteer information sheet, available here.

Yes. We are inviting TwinsUK members to take part in this study whether or not you have received a COVID-19 vaccine (either one or both doses) or a booster shot.

Yes you can still take part in this study, but please wait until 14 days after your symptoms first appeared to complete the blood collection.

TwinsUK is working with the Department of Health and Social Care to understand how many people currently have antibodies and how antibody status changes in people.

We are also working with blood testing company Thriva, who we and other population cohorts worked with previously to collect and test blood samples. This will allow us to collect blood samples from participants in the same way as before.

More information about our work with Thriva can be found in our substudy information sheet, available here. Thriva are certified to handle data securely and will only use your address details for this study. Thriva will erase your data once this study is completed.

More information about Thriva can be found on their website.

Thriva, the supplier of the blood collection kits, has produced a video available here. Please be aware there may be minor differences between your kit and the one demonstrated in the video. Make sure you read both sides of the instruction sheet provided in your kit before starting the blood collection.

Yes please. Thriva will do their best to test your blood for antibodies, although this may not be possible if the volume of blood collected is too small. Do not attempt to prick your finger with anything other than the medical lancets provided.

It is very important that you label your sample correctly, otherwise it will not be possible to identify your sample and we will not be able to provide you with your antibody results.

The instructions leaflet in your blood collection kit contains instructions for how to label and package up your blood sample for the return. Further instructions are available here.

All participation in TwinsUK research is voluntary, and you are free to decline any element of any study. If you decide you do not wish to take part in this blood collection, please put the postal pack in the regular bin.

Please be aware this antibody test is being carried out for research purposes only, and cannot be used to confirm a current or previous case of a COVID-19 infection, or confirm immunity after vaccination.

Please note that antibodies are only one part of the body’s defences against COVID-19. Other parts of the immune system also fight infection, and we did not measure these with this test.

We will email you your antibody research test results within 8 weeks of you sending back your blood sample in the post. We will tell you whether you have clearly detectable antibodies or not, or if the result was invalid.

This means your blood test did not show a clearly detectable level of antibodies against a COVID-19 infection. This could be because:

• You have not been exposed to COVID-19 or had a COVID-19 vaccine.
• You have been exposed to COVID-19 or had a COVID-19 vaccine, but at the time of the blood collection, your body did not show a clear antibody response.
• You have been exposed to COVID-19 or had a COVID-19 vaccine, but have different antibodies that this research test is not designed to pick up.

Please be aware this antibody test is being carried out for research purposes only and cannot be used to confirm a current or previous case of a COVID-19 infection, or confirm immunity after vaccination.

Antibodies are only one part of the body’s defences against COVID-19. Other parts of the immune system also fight infection, and we did not measure these with this test.

You should continue to follow government guidance on social distancing and self-isolation as appropriate. In addition, in line with government guidance, we encourage all TwinsUK members to have the COVID-19 vaccine when offered, regardless of antibody results.

Your blood test showed a clearly detectable level of antibodies against the virus responsible for COVID-19. This means that you may have had or been exposed to COVID-19 in the past and your body has mounted an antibody response, and/or you have received a COVID-19 vaccine:

Clearly detectable Anti-N: Your blood test showed a clearly detectable level of antibodies against a COVID-19 infection. This means that you may have had a COVID-19 infection in the past. Anti-N antibodies are seen in most people who have recovered from COVID-19 but do drop over time. Anti-N antibodies can also be found in people who have been exposed to other coronaviruses. Anti-N antibodies are not produced in response to any of the current COVID-19 vaccines. 

Clearly detectable Anti-S: Your blood test showed a clearly detectable level of Anti-S antibodies against COVID-19. Anti-S antibodies can be found in people who have received one of the current COVID-19 vaccines and/or in people who have recovered from COVID-19. These antibodies are specific to COVID-19 and its vaccines and are not seen after other infections or vaccinations. 

Please be aware this antibody test is being carried out for research purposes only, and cannot be used to confirm a current or previous case of a COVID-19 infection, or confirm immunity against COVID-19. 

You should continue to follow government guidance on social distancing and self-isolation as appropriate. In addition, in line with government guidance, we encourage all TwinsUK members to have the COVID-19 vaccine when offered, regardless of antibody results.

This means we do not know whether you have antibodies or not, as the test did not work properly with the blood sample provided. This may be because your blood sample was delayed when in transit back to the lab, which affected the quality of the blood sample. At this time, we are unable to send out additional blood collection kits for further testing, but there may be other opportunities in the coming year to take part in another antibody test.

You should continue to follow all government guidance on self-isolation and social distancing as appropriate. In addition, in line with government guidance, we encourage all TwinsUK members to have the COVID-19 vaccine when offered, regardless of antibody results.

Antibody levels change over time from the point of infection. This difference in results may be because:

• Antibody status (both the level of the antibodies and the type of antibodies) changes over time from the point of infection, and so antibody levels may have increased or declined compared with other tests done at different times.
• This is an antibody research test only, and may use different criteria to detect antibody levels that may differ from other tests.
• This antibody research test was performed using fingerprick blood sent via post. This means the quality of the blood will be lower than that produced with some of the other antibody test conditions, which may affect the antibody research test result.
• In addition, different antibody tests can measure different antibody types, which can also lead to differing results.

Please be aware this antibody test is being carried out for research purposes only and cannot be used to confirm a current or previous case of a COVID-19 infection, or confirm immunity after vaccination.

In addition, antibodies are only one part of the body’s defences against COVID-19 – other parts of the immune system also fight infection, and we did not measure these with this test.

Please be aware that all participants should continue to follow guidelines on self-isolation and social distancing as appropriate, regardless of antibody status.

Antibodies are only one part of the body’s defences against COVID-19. Oher parts of the immune system also fight infection, and we did not measure these with this test.

Other reasons could be because: 

• The symptoms you experienced were the result of a flu or other bug, and you have not been exposed to COVID-19. 
• You may have been exposed to COVID-19 or had a COVID-19 vaccine, but at the time of the blood collection, your body did not show a clear antibody response.
• You may have been exposed to COVID-19 but have different antibodies that this research test is not designed to pick up.

You should continue to follow all guidance on self-isolation and social distancing as appropriate. In addition, in line with government guidance, we encourage all TwinsUK members to have the COVID-19 vaccine when offered, regardless of antibody results.