Do I have Covid antibodies due to either past infection or vaccination?
Covid-19 Antibody Blood Test (from 29th March 2021, we are using the Roche spike protein, combined IgG/IgM test)
- For those aged 12 and over
- Short clinic visit, by appointment
- Small blood sample taken from your arm
- Result e-mailed to you in 2 days (for samples taken on Fridays after 1pm: 4 days)
- €135 in total (appointment, sample-taking and communication of results to you).
- In use from: 29th March 2021
- Manufacturer: Roche (Switzerland)
- Test name: Sars-CoV-2 spike protein, combined IgG/IgM antibody blood test
- Processing laboratory: SCDL-Eurofins, Sandyford, Dublin 18 (part of the French multinational Eurofins-Biomins)
- Sample type: blood sample taken by us from a vein in your arm
- Time for result to become available: 7 days
- How the result is sent to you: by e-mail direct to you from our doctor. You receive a pdf of the test result plus an interpretation from our doctor of the result significance
- What the test tells you: whether you have detectable antibodies against Covid (specifically against the 'spike' protein on the surface of the Covid virus)
- What information appears on the test result: a numerical figure as to the amount of IgG/IgM Covid spike protein antibodies that are present (<0.8 U/ml = 'negative' and >0.8 U/ml = 'positive').
- What you should read into the antibody quantity result: nothing. There is no scientific consensus yet that the numerical figure has any significance. I do not recommend that you do repeat testing to 'track' your antibody levels (rising, falling).
What scenarios should lead to a positive result?
Past Covid infection or past Covid vaccination
If you're having the test done to see whether you have evidence of having responded to the Covid vaccine, how long should you wait after the first dose of vaccine before having the test done?
At least 14 days and better still, 28 days.
What makes this test more useful than the Abbott (nucleocapsid protein) test we have been using from 22nd May 2020 – 28th March 2021?
The Abbott test remains negative after vaccination and works only if you have had Covid infection. The Roche spike protein test picks up evidence of vaccination as well as evidence of infection.
What are the weaknesses/limitations of this test?
- The antibody quantity has no meaning, currently.
- If you receive a positive result and you have been vaccinated, we won't be able to tell you if you have also had Covid infection in the past or not.
- If you receive a negative result after having been vaccinated, we won't be able to tell you if you have protection or not (a negative result post-vaccination does not equal 'no immunity'!). We will not be recommending you be re-vaccinated.
What is the strength of this test?
Some patients who have been vaccinated and receive a positive result will just feel 'better' knowing they have a proven antibody response. There is nothing wrong with wanting this psychological reassurance.
How accurate is the Covid-19 antibody blood test?
A positive result provide near-100% certainty that you have either been vaccinated against Covid or had the infection or both (but does not distinguish between those two scenarios)
A negative result means you do not have detectable Covid antibodies; if you have been vaccinated, this does not mean you are unprotected. If you have not been vaccinated yet against Covid, a negative result means there is an 80% – 90% chance you have not had Covid infection.
Who is the Covid-19 antibody blood test not suitable for?
- Those with current infection (the test will provide a negative result, unless you have already been vaccinated). If you are in this category, you must follow these HSE instructions: Symptoms of Coronavirus
- Those who have had the infection in the past 14 days (the test will provide a negative result, unless you have already been vaccinated). If you are in this category, you should be following these HSE instructions: Symptoms of Coronavirus
- Those who have arrived in Ireland recently from another country and should be self-isolating. You should follow these HSE instructions: Travel and Coronavirus
- If you live with someone who has current Covid symptoms or a current Covid diagnosis. You should be self-isolating and be following these HSE instructions: Restricted movements for close contacts
- At our clinic, we are not offering this test to those aged under 12 years of age.