The Covid test shows positive even though it's another coronavirus altogether?

[whattheheckactually]

I have a very sensible and clever friend who is a health care professional working with the Covid vaccination trials in the UK.

She mentioned to me that the current covid test picks up other - less dangerous - coronaviruses, eg ones that have been around for years and which we have all caught in the form of a winter cold.

I cannot get my head around this. If correct it raises all sorts of questions, including:

• is this the real reason why we have so many asymptomatic people?
• if someone gets a normal cold, will they test positive for coronavirus and have to isolate, with the impact on their families, jobs, colleagues etc.
• is this the reason why positive numbers are so high?
• is it only certain coronaviruses that can show a positive result?

Or is she wrong altogether?

I know my own family have had two bouts of winter cold symptoms this autumn already but testing revealed we were negative for COVID 19.

It is all so confusing and her statement that the COVID 19 test picks up all sorts of other coronaviruses has sent my head into a spin. As I said, my friend is very level headed and sensible, and she would not want to have scared me (I'm immuno compromised).

Does anyone here have any knowledge about this please?

So what about false positives from swabs that haven't been used? A nursing friend of mine was so dubious about the results coming back to her ward she sent a couple of unused tests to be tested in her hospital. Both came back positive. It's a farce.

No, that's a lie. All of it.

I know her well actually, she's a Sister on a ward. She knows her stuff. I've no idea of how she did it paperwork wise or on what terms but I believe her as do others who know her. But as with everything we're all able to decide what we think.

wherestheotherone well then your friend should be suspended for misconduct. What she did was unconscionable. I suggest you report her.

The PCR test can pick up dead fragments of a previous Covid 19 infection - up to 74 days. It is far from perfect.

@wherestheotherone, you believe her, yet you know to do this she would have to behave unethically in a way that would get her on a gross misconduct charge? I'd be reevaluating what type of person she is. She's putting patients at risk and wasting time and resources.

I think fisherman's tails are going to be renamed HCP's tails, after this.

I think the confusion may have come from antibody tests, which can show cross reactivity with antibodies from one of the common human coronaviruses.

The PCR test for SARS-Cov-2 should identify its own specific viral sequence and therefore not pick up other coronavirus, although there are false positives and negatives in general.

That said those replying about having cold symptoms and being negative, your argument is irrelevant to OP's post (even if your principle is right) because common colds are caused by rhinoviruses as well as coronavirus strains, so even if the PCR test were picking up other coronaviruses you could easily test negative with cold symptoms due to a rhinovirus. But all that is a red herring really because the PCR test should be specific for Covid-19 and not the other coronaviruses.

Like I said believe what you want. At least I respect your right to come to your own conclusions.
I'm not interested in nasty threads!

but the inforamtion is wrong and dangerous @wherestheotherone

wherestheotherone not interested in 'nasty threads' AKA threads in which you're asked to justify spreading ridiculous rumours?

That is such a slippery slope your friend is on @wherestheotherone , if she did that because she didn't believe some of her patients were positive for covid, which is what you are suggesting, what else doesn't she believe ?

Either she was supposed to swab a patient and didn't and sent the swab off pretending she had or she used patients details falsely to allow the swab to be tested. In both scenarios she has acted completely unethically and really should be considering her position.

The ONS random mass testing during the summer (when prevalence was low) produced very low positives, so we know that the maximum potential level of simple false positives is tiny. As time has gone on the positivity rate has gone up and up in a way which fits perfectly with an epidemic sadly progressing as expected.

The “93% false positives” thing on Facebook is a misunderstanding of the theoretical potential issues with random mass testing in a population with very low prevalence. The test results we’re doing at the moment are not random, they’re targeted on people with symptoms, and the population prevalence is high and growing rapidly so the simple false positive rates will not be a significant factor.

I’m a statistician so I understand that bit for myself.

I’m not medically qualified to judge the slightly different theory that the tests are now picking up colds rather than corona, but I think it’s bollocks anyway because a) the qualified virologists who designed and work with the tests are not idiots and say it’s bollocks b) the data from the Southern Hemisphere where some countries have gone through a winter with very low corona positive rates is incompatible with this theory c) the recent increase in hospitalisations fits the pattern of the increase in positive Covid tests.

wherestheotherone if nothing else, they would have come back inconclusive if unused as the lab would have nothing to run. But your story is bollocks, sorry.

One of my hats is medical regulation. Can confirm: tests can only be sent off with a bar code with a patient’s details. Could you send an unused tube off with no bar code? Yes - but it wouldn’t be processed and there would be no way of tracing what happened to that tube or the result from it even if it were.

Falsely sending off a test under a patient’s name would be misconduct. The consequences if found out would almost certainly be suspension at best or possible erasure.

Not saying she didn’t do it (never underestimate the ability of people to fuck up their careers in new and inventive ways) but she wouldn’t be bragging about it at work.

IME it's pretty common for normal, respectable people to report urban myths as though it actually happened to them.

I didn’t think this was true, I thought the test was specific to the Coronavirus that causes Covid 19?

Oxford Uni say there are 6 different Covid Strains.
So your friend is right, but we all already knew that, as the UK was different to the US one .

www.sciencedaily.com/releases/2020/08/200803105246.htm

@MsWarrensProfession

The ONS random mass testing during the summer (when prevalence was low) produced very low positives, so we know that the maximum potential level of simple false positives is tiny. As time has gone on the positivity rate has gone up and up in a way which fits perfectly with an epidemic sadly progressing as expected.

The “93% false positives” thing on Facebook is a misunderstanding of the theoretical potential issues with random mass testing in a population with very low prevalence. The test results we’re doing at the moment are not random, they’re targeted on people with symptoms, and the population prevalence is high and growing rapidly so the simple false positive rates will not be a significant factor.

I’m a statistician so I understand that bit for myself.

I’m not medically qualified to judge the slightly different theory that the tests are now picking up colds rather than corona, but I think it’s bollocks anyway because a) the qualified virologists who designed and work with the tests are not idiots and say it’s bollocks b) the data from the Southern Hemisphere where some countries have gone through a winter with very low corona positive rates is incompatible with this theory c) the recent increase in hospitalisations fits the pattern of the increase in positive Covid tests.

Yeah, the 93% thing is only true when the rate of Covid is 1/10 the accuracy of the test.

If we were testing 100k a day in the summer, and the +ive rate was 1k, then even with zero cases the false +ive couldn't have been more than 1%.

I work on the Covid diagnostic tests. They are thoroughly tested for cross reactivity.

@Reallybadidea it reminds me of the Matron/Sister/paediatric nurse at the LGI story doing the rounds last winter , the one where a lady sent a letter to the Yorkshire Post and the Editor replied with a very informative letter about misinformation and social media.

HCP are not scientists and do not understand the science of many assays that they report the results of. They are not the font of all biological wisdom some seem to think they are, they are specialists in the care of patients. I'd not trust a HCP to run a qPCR assay (the antigen test) or an ELISA (the antibody test) never mind assess the accuracy or precision. But as MsWarrensProfession says the scientists do know what they are talking about.

'I know her well actually, she's a Sister on a ward. She knows her stuff. I've no idea of how she did it paperwork wise or on what terms but I believe her as do others who know her. But as with everything we're all able to decide what we think'

Strange that, I'm a district nursing sister, my small OOH team of 10 have been tested weekly for 2 months, not a single positive result. Your 'friend' is an idiot, at best.

I tested negative with a cold. (Didn't realise it was only a cold when i ordered the test

Sounds like a load of cock and balls to me.

Erasure?

Sounds... final.