How confident do you feel about swab test results?

[CranberriesChoccyAgain]

I went into hospital mid-December with chest pain, dizziness and palpitations. Upon entering A&E I was given a swab test for covid. Standard procedure I assumed with the pandemic. I get told about 3-4 hours later that the test came back positive. They immediately put me in a separate room and eventually I get admitted to a cardiac unit awaiting an angiogram. On day 3, I was given another swab test and blood taken. Day 4 a nurse comes in to tell me the second test came back negative. When I asked about the blood work, I was told it was negative for covid antibodies.

It was never explained how all three tests could be right. I was also told by a different nurse that I should never have been given that second swab test. 🙄 Well why not?

I never had any symptoms, neither did the other three members in my household.

I'm concerned that public policy is heavily influenced by tests that aren't reliable.

I went into hospital mid-December with chest pain, dizziness and palpitations.

What do you mean you didn't get symptoms? You didn't seem to have respiratory symptoms, but covid isn't simply a respiratory disease, or at all. Some people have classical symptoms, but others have other symptoms that can include chest pain and dizziness.

It is possible that you went to hospital late in the progression of the disease, and then you eliminated the virus. It is possible that the viral load down your throad/nose wasn't high. It is possible that you never developed antibodies.

www.cdc.gov/coronavirus/2019-ncov/symptoms-testing/symptoms.html
www.ncbi.nlm.nih.gov/pmc/articles/PMC7492824/
www.scientificamerican.com/article/covid-19-can-wreck-your-heart-even-if-you-havent-had-any-symptoms/

That's a lot of "possible" scenarios. A simpler explanation is a false positive.

The cardiac symptoms I had were identical to an episode I had 2 years ago. I wasn't admitted due to covid. They wanted to make sure there were no blockages or narrowing of my arteries.

I remain very skeptical of the initial swab result, especially since the other 3 adults in my household never developed any symptoms.

It's not that I don't think covid is real, more that I think a lot of scare mongering is happening.

You wouldn’t have developed antibodies that quickly, so I’m not surprised that was negative. And the PCR test is only accurate for the first 5 days, so if you were tested on day 3 first and then day 6 the day 3 result is the more reliable result. I can’t see that they’ve done anything wrong.

@FlyingFlamingo

You wouldn’t have developed antibodies that quickly, so I’m not surprised that was negative. And the PCR test is only accurate for the first 5 days, so if you were tested on day 3 first and then day 6 the day 3 result is the more reliable result. I can’t see that they’ve done anything wrong.

There was no day 6 test. Day zero or one if you like was positive. Day 3 negative.

Reposting from another thread:

If we look at Fig. 1 in this article, we can see that for a number of symptomatic patients, even several days after onset of symptoms, IgA and IgM are negative (undetectable even), and IgG only turns positive for all sometime after day 14.

This is a typical scenario for serology done for any disease.

So, day 3 after a positive rt-PCR test it is perfectly possible to have a negative serology test, even if done to all Ig types.

www.ijidonline.com/article/S1201-9712(20)32199-8/fulltext

If you don’t know when you were infected then you don’t know when day 1 was, I was just using those numbers as an example. Day 1 could have been the day you tested, or a few days earlier.

Actually, higher positivity rates for the test start from day 5 POST-INFECTION and peak at day 7 usually, and it becomes increasingly likely that a negative result comes out. There's quite a lot of variation person-to-person and according to the sensitivity of the test (sensitivity is the capacity to detect all positives, and less sensitivity means more false negatives).

Example: assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/895843/S0519_Impact_of_false_positives_and_negatives.pdf

Progression of the disease is also interesting, as many people end up having it worse towards the end of it, days 9-10. It could well be that the virus had been silently affecting your lungs and heart (it has been described in asymptomatic people), and you only felt bad enough to go to hospital towards the end of the progression of the disease. By this time, though, viral load tends to be lower, and it would mean that 3 days later the rt-PCR was likely to be clear indeed. It is considered that symptomatic people aren't infectious 10 days after onset of symptoms.

www.nytimes.com/2020/04/30/well/live/coronavirus-days-5-through-10.html

So, before you rush to consider your first test a false positive, there is a lot to know about the disease and the tests.

In summary, my best educated guess is that you went to hospital and got tested towards the end of your covid progression, the rt-PCR test turned negative, and it was too soon for a reliable antibody test.

This without knowing how your initial rt-PCR test is done. It is also possible that there were problems with it. But your symptoms were consistent with covid-19, yes.

What symptoms? No fever. No loss of taste or smell. No cough.

I had an identical cardiac episode two years ago. Are you suggesting I had covid then too?

Nah, I'm going with the simplest answer, a false positive.

There are plenty of reported cases of people with no symptoms testing positive, or people with positive antibodies who never had any symptoms. But you seem to know better, so what exactly was the point of this thread, or were you just hoping to start an argument?

Let’s just stop testing people admitted to hospital and let the 90 year old lady with a broken hip mix with the patient opposite unknowingly carrying Covid on the ward, and when she gets infected she can take it back home to her care home and then she can infect everyone else there, a few people might die but at least there won’t have been any false positives

False positives are far rarer than false negatives.

@Backyard72

False positives are far rarer than false negatives.

How would we know that? If someone tests positive, how often are they given a second test? We are assuming an initial positive result is accurate and that person gets added to the stats for that day/week.

I was told by a nurse that I shouldn't have had that second swab. Why not?

To the other poster, of course I don't think we should stop testing. But I worry about guidelines being based on tests that seem (to me) unreliable.

I was told by a nurse that I shouldn't have had that second swab. Why not?

Probably because you didn't need it after a positive result. And given the false negative rate, it isn't very useful to show that you were no longer infectious. That's the test you should be weary of.

Do you mean wary? Yes, I agree, we should be wary of the numbers purported out there.

What symptoms? No fever. No loss of taste or smell. No cough.

Did you read my links? Those are not the only symptoms. They may be frequent, but many people don't even have symptoms. And your symptoms have been recognised as present in people with covid.
It could be a coincidence, but your previous episode shows you are have a susceptibility, and you can't say that you didn't have symptoms at all. You went to A&E, fgs. You were ill. With symptoms that match some found in covid patients.

I had an identical cardiac episode two years ago.

And for all you know, you could have had a viral infection in the previous episode.

The most likely explanation for your case is that you had a somewhat less frequent form of covid, but a form that has been recognised as a worry.

www.ucsf.edu/magazine/covid-body

"But as the number of infections climbed, the symptom list began to grow. Some patients lost their sense of smell and taste. Some had nausea or diarrhea. Some had arrhythmias or even heart attacks. Some had damaged kidneys or livers. Some had headaches, blood clots, rashes, swelling, or strokes. Many had no symptoms at all."

This is an educational article that you might find useful. Definitely worth scrolling down to the vascular aspect of the disease.

Yes, wary. :)

And the test you should be doubting more is the negative rt-PCR one, along with the serological test.