Antibody tests - had one and it's negative and I now feel really upset

[FacingMyWaterloo]

I know this might sound ridiculous and I'm partially posting for you all to slap me round the face with a wet fish...

I work in central London and have a train/tube plus bus or walk commute. I'm defined as a key worker and though I have been able to do some work at home, I've also still had to go in, on and off.

In the middle of March, I had the coronavirus symptoms. 3 days after I came down with them, my partner (who is asthmatic, and works from home anyway) got the same symptoms as me but worse.

I need to do more work in town v soon so thought for peace of mind, we would have a private antibody test. We were absolutely convinced we had had it. His has come back positive and mine is negative and I feel totally devastated. I actually wish we hadn't had them done now. I did read there is more chance of a false negative and there are some people whose antibody levels don't pick up enough to test anyway.

Please talk some sense in me because for some reason I feel utterly miserable about it. Dp is of course delighted and now feels invincible yet he's the one who gets to stay at home anyway!

If he definitely had it and it's that contagious, seems strange you haven't!

I don’t know how much you can rely in the test, doubtful that it’s accurate.

But there have been early studies into some mild cases who do not produce antibodies. So you may have had it mildly, although that doesn’t really help you.

In the plus side your at risk dp is ok having had it, silver lining. Big caveat - if the positive test is accurate and having it means you are immune. Lots of unknowns.

Heard recently from a test provider that antibody tests are 30-70% inaccurate - a false negative is a strong possibility.
If your partner had a positive and you had a negative then you may well fall into false neg category

Just for context - had a detailed convo with them - not just read on internet

I think if you and your bf had similar symptoms at the same time it’s more likely you either both had it, or both had something else.

If false negative are more likely than false positive I’d guess your test is wrong and you both had it.

There are reliable private antibody tests but they are lab based not rapid testing which are the ones the papers are talking about mostly. The Government was looking into rapid testing. Obviously there is a way to check for antibodies in a lab but these tests are expensive and sometimes not scaleable to be rolled out in the volume required by the general public. The rapid ones that are instantaneous were the cheap ones they were trying to roll out. Reliable antibody testing is available privately at a cost for those willing to pay.

No one worldwide has developed a working antibody test.
The "have I got it now" test is only 70% reliable.

@PeppaPigOinkOinkOink only 60%? I thought it was 75% and that's bad enough! Hope you feel better soon.

Looks like you lost your money OP, they aren't reliable enough yet.
Guess there's one born every minute.

in general coronavirus antibodies only tend to last for 18 months. its expected the covid strain will be the same. Many people won't be able to make the antibodies if infected due to lack of Tcells. Children tend to have more of these cells and it appears one reason they fight it off easier. If you do have the antibody you can still be infected but it would likely be milder (like when you have a vaccine) The real problem will be when the next wave hits next year s its expected to circulate the flu does. If it had been contained in the beginning it may have been eradicated for the most part like previous sars strains.

OP these tests aren't accurate otherwise the government would have been all on it. Sounds like you've been scammed.

I wouldn't assume you or your husband have or haven't had it based on these tests. There's also lots of info coming out that there's many strains about so even if you've had one strain there's limited evidence to say you can't catch corona again.

You are all confusing rapid antibody testing (which is v inaccurate at present) and laboratory based testing which is expensive but very accurate!

Oaktree yes the accurate rapid home test doesn’t exist yet.

I do wonder when we’ll see the results of the small U.K. test.

The rapid tests are junk. Not sensitive enough and not specific enough (many ping for standard coronaviruses — the ones that cause the common cold).

Are you sure? The Harley Street doctor is fraudulently offering tests so..

@FacingMyWaterloo you have no way of knowing if you or your family have had Covid 19 as none of you were tested for it. My dad had a positive test result from a HSE (Irish equivalent of NHS) test done in the town he lives in in Ireland. My mum had symptoms of nasal congestion, sore throat and diarrhoea. She was supposed to have a HSE test done last week but due to her GP making a computer error she only has it on Wednesday. She was phoned by the GP yesterday evening to say she was negative. So we don't know if she has had it or not due to the delay in testing.

We have a family friend in hospital in a coma and on a ventilator, she is apparently not positive for corona The person I caught it from ended up in hospital and was tested negative as well.

I would take the results with a pinch of salt.

Catherine there are early studies that have shown positive turns to negative over time. Although you’re probably talking about antigen test rather than antibody.

Ahhh @MarshaBravado. Interesting.

@FacingMyWaterloo hang on. You think you had an antibody test without giving blood? How is that possible.

I did see there are a few places taking blood to

Blood is the place to look for antibodies

I used to do a lot of antibody tests.
You need to look at the sensitivity and the specificity.

There is also a lot of questions about the level of antibodies and time.

A test that is 86% sensitive isn't that helpful. If you get a negative test, there is a reasonable chance that you have had the disease and have antibodies.

Even if it's done in a hospital lab and is quantitative.

But someone somewhere is making money out of this.

You are all confusing rapid antibody testing (which is v inaccurate at present) and laboratory based testing which is expensive but very accurate

How are you defining accurate?

Specificity and sensitivity are very important when it comes to discussing lab tests.

It was blood @Starrynightsabove but a quicker test rather than it being sent away for testing

but a quicker test rather than it being sent away for testing

You can either have a test like a pregnancy test that just says positive or negative - or a test that calculates the level of antibodies in the sample - which can be done in a local lab rather than being sent away -

An example of these tests is here - along with a good discussion of positive predictive value

www.evaluate.com/vantage/articles/analysis/spotlight/covid-19-antibody-tests-face-very-specific-problem

Sorry I was probably using the wrong terminology. I am very rarely ill - I can't even remember the last time I went to the Gp :). But have dcs with asthma and dp has asthma too.

It was a test where they took blood from my finger rather than a needle in my vein. So yes one of the rapid ones - on reading those articles they do seem to have an issue with false negatives.