How it works
- Purchase your test online here
- Arrange your phlebotomy visit
- You will receive your home sample kit via express delivery (next working day delivery if ordered before 2pm)
- Register your kit using our online form
- Have your blood taken by a professional phlebotomist and label your blood tubes (labels are provided)
- Return your sample by using the pre-paid envelope provided (this can simply go in any post box)
- Receive your results by e mail within 1-2 days of your sample reaching our laboratory
What’s in the kit?
- 1x detailed instruction sheet to tell you how to easily register your kit with us
- Labels for your blood collection tube
- 1x biohazard bag
- 1x pre-paid return envelope
What does my antibody test result mean?
An overall result of “Negative” means that any IgM or IgG antibodies to the SARS-CoV-2 (the virus that causes COVID-19) S1 spike protein that may have been present in your blood sample were not detected by our test. This could be because:
- You have been infected, but your immune system has produced antibodies that do not bind to the SARS-CoV-2 S1 spike protein in our test
- You have been infected, but the infection was mild and the antibodies you produced are below the detection limit of our test (if you have had typical COVID-19 symptoms, the first two of our three explanations are the most likely explanations)
- You have not previously been infected.
Receiving an overall result of “Positive” from our test confirms that you have had COVID-19 in the past and that your immune system has mounted a memory immune response against the virus that is detectable by our test – a positive result for either IgM or IgG gives an overall positive result. For those that are positive, we will also show you whether you have a low, medium, high or very high amount of antibodies to SARS-CoV-2, with a numerical value for your antibody level – indicating the strength of your immune response to SARS-CoV-2.
Obviously the stronger your immune response to the virus the better, but it is Professor Johnston’s belief that even a low positive antibody level in our test is actually evidence that you have a strong immune response to the virus.
This is because the MHRA required all companies developing antibody tests to set their cut-off for a positive test high (to avoid companies giving out false positives). This has resulted in all tests missing antibody responses in milder cases – we missed 13% in our validation cohort of community COVID cases – so the ones we do actually detect are at the stronger end of the antibody response spectrum.
Past experience with seasonal coronaviruses tells us that it is highly likely that the presence of detectable antibodies does confer protection against repeated infections. In one study people who had mild symptoms after they were infected with a seasonal coronavirus, were all protected from having symptoms when they were re-infected with the same seasonal coronavirus a second time one year after the first infection. It is likely that people who developed symptoms with COVID-19 that were more significant than mild, will have developed a stronger immune response and will therefore be protected to a greater degree than the protection seen in the above study with mild symptoms with a seasonal coronavirus.
Further test details:
Who is this suitable for?
Anyone who would like to know if they’ve previously had COVID-19. This is the ‘have you had it’ test. If you currently have symptoms of COVID-19, you should follow government guidelines (https://www.gov.uk/coronavirus).
What’s the advantage of this test?
Two different antibody types (IgG & IgM) are tested
This test measures levels of two antibody types (IgM and IgG) against SARS-CoV-2. As some other tests only detect IgG antibodies, this test should detect an additional proportion of people who have detectable IgM antibodies but do not have detectable IgG antibodies.
Our test gives you a quantitative result
If you have a positive test result, this test will also tell you how strong your immune response to SARS-CoV-2 is, with antibody levels reported as low, medium, high or very high. This will also be given a numerical value, which gives you a baseline measure so you can check in the future whether your levels have changed over time.
Antibodies that our test detects are likely to be protective against SARS-CoV-2 infection
This test has also been tested against a SARS-CoV-2 neutralisation test (a test to see whether the antibodies in your blood are able to stop the live virus from entering and infecting cells) and both IgM & IgG antibody levels measured by our test correlate very strongly with virus neutralising (blocking viruses from infecting cells) activity. So, if you have a positive test it is very likely that the antibodies our test detects will be protective against SARS-CoV-2 infection.
Spike S1 protein test
This test detects antibodies to the S1 Spike protein, instead of the more widely used Nucleoprotein, therefore we would expect 10-15% of users that may have tested negative on a Nucleoprotein-based test to test positive on ours.
How accurate is this test?
This test has been shown to detect 100% of severe hospitalised cases and 86.9% of 107 milder community cases, including asymptomatic people with a positive SARS-CoV-2 swab test, this is the test sensitivity. Most other tests have not been validated in community cases of COVID-19, nor in asymptomatic people with a positive SARS-CoV-2 swab test.
For high or very high positives, the specificity of our test is 100%. This means for moderate to very high antibody positives, we are almost 100% certain they are not false positives. For moderate level positives, the specificity of our test is 99.5%. This means for moderate antibody positives, one in 200 tests could be a false positive. For low level positives, the specificity of our test is 98.6%. This means for low antibody positives, 1.4 in 100 tests could be a false positive.
Note that in Prof Johnston’s view, a “false positive” is probably more likely to be showing cross-reactive protection from prior seasonal coronavirus exposure, than being a true false positive.
How quickly will I get my results?
Within 1-2 days of the lab receiving your sample.
We return your samples to us by Royal Mail Tracked 24 hour, delivering your samples to us usually on the next working day.
Is this an approved test?
Yes, the COVID-19 S1 antibody test is CE marked (accredited), meaning that the products we use meet EU safety, health and environmental requirements and are approved for use within the European Economic Area (EEA).
Why would I choose this option instead of a finger-prick sample kit?
Some individuals prefer arranging a professional phlebotomist to take their blood sample, as they may find this option easier than taking the finger-prick sample at home.