Antibody testing can detect if a person has developed an immune response to COVID-19, either because of past infection or because they have had the vaccine. Antibody tests cannot diagnose current infection and not everyone will develop an antibody response to COVID-19 infection or vaccination.
At Northway Clinic we offer 3 different antibody tests
- COVID-19 (SARS-CoV-2) Roche Elecsys Anti-SARS-CoV-2 S (SPIKE) – This is the test to have if you want to check the amount of antibodies you have after vaccination. It can also show the amount of antibodies after infection. It will show a positive or negative result, and give the quantity of antibodies detected. A blood sample is sent to the laboratory and you will usually receive your results by email 24 hours after having the test.
- COVID-19 (SARS-CoV-2) Roche Elecsys Anti-SARS-CoV-2 Total Antibody – This test is only for after infection. Some people will develop antibodies to both the spike RBD and nucleocapsid and some people will not develop any antibodies at all. It will show a positive or negative result. You can combine this test with the SPIKE test for a comprehensive overview of your immune response after infection. A blood sample is sent to the laboratory and you will usually receive your results by email 24 hours after having the test.
- INSTANT TEST – The test we use is a NADAL® COVID-19 IgG/IgM Rapid Test which is legal for use by healthcare professionals in the UK. You will receive your results 10-20 minutes after providing your sample. A healthcare professional will take a blood sample for the test. The test we use shows a sensitivity of 97.4% for IgG antibodies and 86.8% for IgM antibodies and a specificity of 99.3% for IgG and 98.6% for IgM. It is less accurate than a laboratory test but gives a quicker result. Test results must be interpreted by a healthcare professional in conjunction with all available clinical information.
What are COVID-19 antibodies?
Antibodies are part of the immune system. They help the body to recognise harmful substances (like viruses) and mount an immune response to remove the harmful substance from the body. There are many different types of antibodies.
After infection with COVID-19, you may have detectable antibodies to both the nucleocapsid (N) and the spike protein receptor binding domain (RBD). Antibody tests for both nucleocapsid and RBD antigens can be helpful to identify if you have been previously infected with SARS-CoV-2. It is not yet known if having a positive antibody test after infection with SARS-CoV-2 means you will be protected, either fully or partially, from future infection or for how long protective immunity may last.
After vaccination against SARS-CoV-2, with no history of natural infection, the antibodies you develop are to the spike protein receptor binding domain.
When should you get an antibody test?
Antibody testing should be performed 14 days or more after the first day you had symptoms, known exposure to COVID-19, or you had the 2nd dose of the COVID-19 vaccine. Remember you will have to self-isolate for 10 days if you have tested positive for COVID-19.
Why should you get an antibody test?
It is not yet known if having antibodies will protect you from getting COVID-19 completely, or at all. Antibody tests are useful to find out how many people have had COVID-19, if the vaccination has produced an immune response, and how long antibody levels last (if you have repeat tests).
How is the antibody test done?
You will have to attend Northway Clinic and have a blood sample taken by a trained healthcare professional. This will be sent to the laboratory for analysis and the results usually take about 24 hours to come back.
How accurate is the Spike Antibody Test?
The Anti SARS CoV-2 S (Spike) Total Antibody test has 99.8% sensitivity and 98.8% specificity for SARS-Cov-2 in samples taken 14 days or more after a positive PCR test.
How much does a Spike Antibody Test cost?
The test costs £62 which includes the cost of the appointment and laboratory analysis cost.
Please note we currently add a £5 surcharge to all appointments to cover the additional costs to the clinic of PPE and other COVID-19 safety measures. This is kept under continuous review.