Do / Did I have COVID?

[GGD]

Fri 03/04/2022 10:30AM iHealth Rapid Test - Positive
Fri 03/04/2022 10:45AM iHealth Rapid Test - Positive
Fri 03/04/2022 11:00AM QuickVue Rapid Test - Positive

Mon 03/07/2022 11:30AM QuickVue Rapid Test - Negative
Mon 03/07/2022 03:35PM PCR Test Stanford - Negative

The two iHealth tests were from different packages obtained in two different parts of the country weeks apart.
The two QuickVue tests were from the same package.

I had no symptoms, I only tested because we were about to leave for a family gathering. I began isolating and wearing an N95 immediately.

My wife tested negative with the second iHealth test from the box that I used for my second test.

WTF was in my nose on Friday that caused 3 false positives on rapid tests from different batches and brands?

Or, did I have COVID on Friday and it became totally undetectable on Monday? My understanding is that a PCR test is so sensitive that it may give positive results for up to 90 days after an infection.

[Ombligo]

Trust the PCR.

[Pam]

You may have had it but it was gone by the time you took the PCR. I believe false negatives are far more common than false positives.

[GGD]

Pam wrote:
You may have had it but it was gone by the time you took the PCR. I believe false negatives are far more common than false positives.

I learned more about the PCR test over the weekend, it is so sensitive that it can still report positive results in recovered COVID patients for up to 90 days after the start if the infection, this is why they tell patients to not get PCR tests until 90 days after they recover. So if I had it on Friday, the PCR test should still be detecting it.

When to Get Tested

Review the scenarios below to determine when to get tested. If you have had COVID-19 in the past 90 days and recovered, you do not need to be tested unless you develop new symptoms. If you do have new symptoms, consult a healthcare provider for testing recommendations.

https://www.cdc.gov/coronavirus/2019-nco...sting.html

People who have recovered from COVID-19 can continue to test positive for up to 3 months after their infection. CDC does not recommend retesting within 3 months after a person with COVID-19 first developed symptoms of COVID-19 (or the date their sample was taken for their first positive viral diagnostic test if their infection was asymptomatic).

https://www.cdc.gov/coronavirus/2019-nco...0infection

[Tiangou]

Pam wrote:
You may have had it but it was gone by the time you took the PCR. I believe false negatives are far more common than false positives.

False positives are rare with the rapid antigen tests.

With Omicron and its "stealth" variant, you may need to test at peak-symptoms to get a positive at all.

https://news.yahoo.com/false-positive-co...00906.html

“The problem with [at-home tests] is actually the other side, the false negatives, the fact that they’re not very sensitive.” Antigen tests are most accurate when you have symptoms, Dr. Baird says, since that usually correlates to having “a lot of virus” in your body—it’s easier for the tests to detect.

Even a PCR test is more accurate in the first few days after onset and may end up with false-negatives. Omicron can blow through so quickly that it may evade PCR tests if you test more than 3 days after peak symptoms.

The consensus appears to be that you should treat any positive test result as legit. Mask and isolate.

https://news.yahoo.com/false-positive-co...00906.html

If you test positive at home, don’t assume it’s a false positive, especially if you’re experiencing the symptoms of COVID-19. “You should stay home or isolate for 10 days and wear a mask if others could have contact with you,” the CDC recommends. “Also, tell a healthcare provider about your positive test result and stay in contact with them. If your illness becomes severe, seek medical attention.”

[GGD]

Ombligo wrote:
Trust the PCR.

That's my thought too, but I'm asking my doctor if I should get a second PCR this week just to be sure, or three if the first two disagree.

[JoeH]

GGD wrote:
So if I had it on Friday, the PCR test should still be detecting it.

Change that "should" to "might" and that would be a better statement of how it works. A PCR test is more accurate, but the processed in a lab type is best.

[GGD]

JoeH wrote:
[quote=GGD]
So if I had it on Friday, the PCR test should still be detecting it.

Change that "should" to "might" and that would be a better statement of how it works. A PCR test is more accurate, but the processed in a lab type is best.
How about "has a high probability of".

This was a lab processed test, sample collection and processing was all done in-house at Stanford Medical Center. That's also how they manage to get 12 hour turnaround for results.

SARS-CoV-2 RNA Your Value Not Detected
TEST PARAMETERS AND METHODOLOGY
Methodology: Reverse Transcriptase Polymerase Chain Reaction (RT-PCR)

This test is authorized by the U.S. Food and Drug Administration (FDA) under an Emergency Use Authorization (EUA) for use by laboratories certified under the Clinical Laboratory Improvement Amendments (CLIA) to perform high complexity tests.
Validated specimen types: Nasopharyngeal (NP), Nasal and Oropharyngeal (OP) swab specimens. Sensitivity and Specificity are unknown for other specimen types and collection techniques.

[mrbigstuff]

I've read that 3 antigen tests in sequence (not sure daily or what interim) are as valid as a pcr test. But I've also read that one must test very frequently (up to daily) to detect the omicron variant.