Question about at-home COVID tests

[pete6032]

Does anyone know if you have been vaccinated if you take an at-home COVID test will it give a false positive?

 

[allisolm]

No, it won't.

COVID-19 Vaccine Facts

What you need to know about COVID-19 vaccines, myths and facts.

www.cdc.gov

 

[dave_the_nerd]

Mine didn't.

 

[MtnMan]

The vaccine contains none of the virus, either weakened or dead.

 

[Captante]

Negative.

 

[lxskllr]

How's that for service?! You didn't even half to go to the drugstore, and Captante handled it for you. ATOT, your one stop for everything!

 

[Scarpozzi]

I make a lot of jokes on here, but I'm being serious with this response.

I don't know about the at-home tests, but if it's a rapid test that gives you instant results, you could actually get a false positive or false negative more readily. This goes for rapid flu tests as well. You may want to research the liklihood of that happening for flu and then assume the risk is similar for COVID.

Additionally, COVID is a more slippery virus. It usually takes a solid 5+ days after contracting it that you start to get enough viral load that it registers. (my understanding) My wife has sent a few people to get tested that had negative results....only to have them test again 2 days later and come back positive. Just be aware that timing is everything.

 

[dullard]

Additionally, COVID is a more slippery virus. It usually takes a solid 5+ days after contracting it that you start to get enough viral load that it registers. (my understanding) My wife has sent a few people to get tested that had negative results....only to have them test again 2 days later and come back positive. Just be aware that timing is everything.

That was true (actually the best chance for accurate results was to test about 7 to 8 days after exposure). But, the Delta variant multiplies so quickly in your body that you reach a high viral load a couple days earlier. I think we can now start getting accurate results 3+ days after exposure.

 

[dullard]

Does anyone know if you have been vaccinated if you take an at-home COVID test will it give a false positive?

At home antigen tests are not extremely accurate. The accuracy varies from kit to kit and varies on how prevalent the disease is in the area. I suggest that you plan for the worst case scenario with antigen tests: expect 1 in 5 positive antigen results to be a false positive -- whether you had the vaccine or not. There are also a lot of false negatives too with antigen tests.

At home PCR tests are designed to be extremely accurate for positive samples. If you test positive on a PCR test, you should consider yourself to be positive. Roughly 1 in 300 positive PCR tests are false positives -- usually due to operator error. PCR tests however, can have a lot of false negatives. If you are negative on a PCR test, then you might need to test again in a couple of days. Again, this has nothing to do with vaccination status.

 

[pete6032]

How's that for service?! You didn't even half to go to the drugstore, and Captante handled it for you. ATOT, your one stop for everything!

I trust him with my life.

The reason I ask about these at-home tests is I may be traveling to a high-risk area where getting a test may not be possible. I'm fully vaccinated but plan to bring some basic medical supplies with me, including mask, thermometer, o2 meter, and an at-home test.

 

[Scarpozzi]

That was true (actually the best chance for accurate results was to test about 7 to 8 days after exposure). But, the Delta variant multiplies so quickly in your body that you reach a high viral load a couple days earlier. I think we can now start getting accurate results 3+ days after exposure.

That's actually a good thing, I suppose. But I'm going to go back and state that the rapid tests still aren't as accurate as the tests where the geek squad actually looks at the sample. This FDA article blames user error, but I argue it's a limitation of the technology.

Potential for False Positive Results with Antigen Tests for Rapid Detection of SARS-CoV-2 - Letter to Clinical Laboratory Staff and Health Care Providers | FDA

 

[dullard]

This FDA article blames user error, but I argue it's a limitation of the technology.

It is a technology limitation. Antigen tests are checking for one thing and have absolutely no controls (no easy way to know if the test worked or if the user did it properly).

PCR tests require (1) presence of 3' strand DNA, (2) presence of 5' strand DNA, (3) Positive control that amplified correctly to prove that the reagents and equipment were functional, (4) Negative control that does not amplify to prove that you don't have contamination. Thus, all four tests must be passed sequentially for the PCR result to be positive. It is like putting 4 different filters on a signal, the output signal will be pretty clean (if anything comes through). Antigen tests just have 1 filter.

 

[Scarpozzi]

My wife just messaged me that most of her patients today are covid suspects.

Last week, she said 25% of her caseload was covid walk-ins. I'm afraid things are about to get bad for the anti-vaxxers around here.

I posted last week that my cousin who started having MS type symptoms with loss of muscle mass, balance, eyesight, and immune system response caught covid from a caregiver in his home. He ran a marathon with me in 2016....so he's tumbled fast. He spent about 2 weeks in the hospital and somehow was released after battling pneumonia and covid. The vaccine certainly saved him.

I'm really thinking with this new variant, a bunch of people are about to be toast between now and Christmas that are afraid of a few shots.