Antibody test: I had my second Pfizer jab two weeks... - PMRGCAuk


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Antibody test

Smokeygirl profile image

I had my second Pfizer jab two weeks ago and as my family are visiting next week I decided to send for an antibody finger prick blood test. It cost £50 from LloydsPharmacy UK.

The results came in two days. It was positive with 1990 U/mL. I was amazed. My son who is Type 1 diabetic was only 55O U/mL. I have been on Pred for two years and was on 8 mg when I did the test. I have definitely not had COVID and we have shielded from the start. I am delighted of course but——- how do I know if it is a false positive or not? My husband is going to do his test tomorrow.

42 Replies

Do you mean thatyou were positive for COVID antibodies?I have a kit of 7 tests. Completely free, from the NHS. Will be doing them soon.

That sounds like the test you do yourself at home Sheffield Jane. Everyone can access them more (in England). I keep doing one although as I hardly go anywhere it seems a little pointless.

Yes I agree, however I seem to have every long COVID symptom and I am wondering.

Yes, positive for antibodies—— and a lot of them apparently! That is what Lloyds pharmacy said when I phoned up. If it is a true reading , it is very good news for all of us on steroids. Are you sure your kit is for antibodies? I thought the free kits were to test for Covid.

Rancho profile image
Rancho in reply to SheffieldJane

Did you get the test kit from your GP Sheffield Jane or somewhere else via NHS. Is it the one that tells you if you have had covid, if so I assume it also works to tell you if have produced antibodies from the vaccine? Thanks.

SheffieldJane profile image
SheffieldJane in reply to Rancho

I got it on line via the NHS website. Prompted by Sheffield City council who provided a link. It promises to tell me after 30 minutes whether I have the disease. I am not clear whether it can tell me if I have ever had COVID. Or whether it can tell me about antibodies generated by the vaccine - as I understand it - the purpose is to identify people who have COVID without symptoms.

If it is a pack of 7 it sounds like the rapid flow antigen test or lateral flow test that gives you a result in 30 minutes.

PMRpro profile image
PMRproAmbassador in reply to SheffieldJane

Are the kits not antiGEN kits? To test for the VIRUS, not the antibodies? Totally different thing.

SheffieldJane profile image
SheffieldJane in reply to PMRpro

Yes. I hadn’t opened it.A lot of people are making a lot of money out of the fear and uncertainty.

That’s interesting and encouraging. I’m hoping for my second in the next couple of weeks but after catching up on some posts here was feeling rather despondent.

Wow...I didn’t even know they measured the amount of antibodies. My GP said the antibody test here in Ontario, Canada only indicates that yes you have them, or no you don’t.

We are much further behind in our vaccine rollout, so maybe this type of test will be available in the future. Very encouraging though!!

PMRpro profile image
PMRproAmbassador in reply to PMRCanada

It depends on which test is used - and not all are generally available. Like everything - marketing ...

alvertta profile image
alvertta in reply to PMRCanada

We need this!

PMRCanada profile image
PMRCanada in reply to alvertta

Yes we do!!

That’s interesting. We have family coming soon armed with NHS tests so I will see what it says. I might buy the Lloyds test too out of interest. I’ve had the Oxford. What’s the optimum U/ml ?

Smokeygirl profile image
Smokeygirl in reply to Bridge31

I’ve mailed you the chart—- I don’t know how to include it on here.

Rache profile image
Rache in reply to Smokeygirl

That’s reassuring news for you. I’m currently on 5.5mg but not feeling reassured by having had my two AZ vaccines. Sorry to be a nuisance, but could you possibly email me the chart? Will pm you my email address.

PMRpro profile image
PMRproAmbassador in reply to Rache

Bear in mind that different antibody tests will have differing results so you probably can't apply the information from one to interpret the results from a different one.

Rache profile image
Rache in reply to PMRpro

I emailed Monitor my Health who use NHS labs, having used them before for VitD test. I asked them if their results just said yes or no to antibodies or if they showed the actual levels present. They sent the following reply:

‘We report both of our antibody tests (N and S) as positive and negative. We do not currently report the levels of antibodies, principally because this does not currently offer additional information above knowing that the antibodies are present. If the evidence for this changes we will review this decision.’

Think I would still like some indication of the levels though.

PMRpro profile image
PMRproAmbassador in reply to Rache

But it might either depress you or make you over-confident without grounds. The numbers don't necessarily mean anything in that a low level may not mean you don't have protection

Rache profile image
Rache in reply to PMRpro

I understand PMRpro but I don’t think I’d be over confident with all the new variants appearing etc! Having a low result, though disappointing, would make me even more cautious than I am already,

PMRpro profile image
PMRproAmbassador in reply to Bridge31

Are the family coming after using the tests to see if they have the virus?

Bridge31 profile image
Bridge31 in reply to PMRpro


PMRpro profile image
PMRproAmbassador in reply to Bridge31

As long as they know that they are only valid for about 48 hours - our local immunology expert was telling us on the news programme that the ideal way to use them is test on one day and then 48 hours later if the first was negative. They need enough virus to show positive - so if you test very early in an infection they may be negative - but in 48 hours there can be enough virus to pass on so by testing again you are safer since some of the antigen tests miss about 1 in 3 cases.

Slightly worried about my antibodies test now, I did one three weeks after my second AstraZeneca which came back 8.6U/ml that seems very low in comparison. Also could you send me the chart you mentioned below please.

The ones free in London are Lateral Flow Test to check whether you have IT and if you are positive you have to get the PCN test. It is not an antibody test.

My test was a spike antibody test, not sure if same as antibody test. So many on market now so although positive am treating it with caution

Smokeygirl profile image
Smokeygirl in reply to Poshdog

Me too—— worried that the family wont! BTW I think most of them are spike antibody tests —

Poshdog profile image
Poshdog in reply to Smokeygirl

I haven't told anyone for just those reasons, so family still treating me with kid gloves! Is that very bad behaviour on my part?

PMRpro profile image
PMRproAmbassador in reply to Poshdog

No - anticipating bad behaviour on THEIR part ;)

Thank you for the chart it, I am still unsure though if mine are low which they seem to be compared to a lot of other people's results that I've seen. Maybe the Pfizer produces more antibodies than the AstraZeneca or maybe it's because of the steroids, I was on 13mg for my first and 18mg for my second vaccine.

PMRpro profile image
PMRproAmbassador in reply to Chewy21

The evidence available so far seems to be that while the level of antibodies produced varies widely anyway even in healthy subjects not on immunosuppressant medication, being on corticosteroids can suppress the development of antibodies considerably. However, they don't yet know how significant that is in terms of resistance to the virus - so the safest thing to do is have your vaccination and continue to practise the same safe behaviour you have for the last year.

Chewy21 profile image
Chewy21 in reply to PMRpro

Yes I will continue to practise the same behaviour it's just frustrating missing close contact with my family and I thought I would feel safer around them but now I don't feel I have that assurance from the vaccine.

PMRpro profile image
PMRproAmbassador in reply to Chewy21

Which is exactly the right response - too many people are making too many assumptions. Above all, a mutation may develop that the vaccines aren't effective again or that only one sort may work well. But even at best, there is still a chance you can catch it and until the incidence in the population is shown to be really low - that remains higher than I'd want to risk.

Thanks for the information on your journey. I to have had both Pfizer shots (USA) and only had a slight headache after the first one, nothing on the second. I was on 10 mg prednisone at the time of the shots . It's a relief to be vaccinated! Thanks Tom 60 years young Santa Cruz California

At the risk of teaching Grandmothers to suck eggs .......

a) Any test which uses a swab to take a sample from the back of your throat and your nose is an ANTIGEN test. This shows whether you are carrying the virus and, even if negative and/or you are not yet showing symptoms of Covid, you could still be shedding enough of the virus to infect other people. That is why we are being asked to test at least twice a week and to continue wearing masks etc. The PCR-type test (which has to be sent away to a lab to be analysed) is more accurate than the Lateral Flow-type of tests which are available free from most pharmacies. False positive and false negative results are both all too common.

b) An ANTIBODY test has to be done on a blood sample, normally from a finger-prick. These are not yet being done as routine tests. (I did one only because I am part of an official survey group.) These antibody tests will show the amount of antibodies in your BLOOD, either because you have had Covid and have recovered or because you have had the vaccine. However, no-one yet knows how many antibodies you need to be "immune" from catching Covid or from infecting others. All they are saying is that having the vaccine makes you less likely to get seriously ill. Antibodies are only one part of the whole immune system. There are many other factors which contribute to immunity or lack of it. Lots of further research is being carried out but, until we know more, I agree with PMRpro - we need to continue being careful.

Antibody testing is very problematic. It doesn't tell you if you have immunity or not. Here is a link where it is well explained you are still on steroids best to assume you still need to take care. But the vaccination is still worth having even if one gets a low level of protection. It might make one less likely to get severe COVID. Keep safe...and keep smiling!

PMRpro profile image
PMRproAmbassador in reply to agingfeminist

The link doesn't work. This does:

agingfeminist profile image
agingfeminist in reply to PMRpro

Thank you for providing the correct URL!

PMRpro profile image
PMRproAmbassador in reply to agingfeminist

There were 2 extra letters after the last forward slash - most peculiar!!!

So, my husband’s blood test for antibodies came back just now. He has 882.0(U/mL) positive antibodies. Both IgG and IgM.He had the Pfizer same as me. He is 86 and is on a lot of drugs including one for blood cancer to raise his platelets.

Thought this would interest everyone. It is reassuring but I agree that we still have to be very careful.

Good news, I think. I just got my semi-quantitative COVID antibody test results of >250U/ml. Anything over 250 is reported as >250. I've been on prednisone for 3 years for PMR/GCA and currently at 9.5mg. I took the test 10 weeks after my 2nd Moderna vaccine. Until more research is in regarding antibody levels and immunity/prevention of serious illness I will continue to take precautions.

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