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[quote=Anonymous][quote=Anonymous][quote=Anonymous][quote=Anonymous][quote=Anonymous][quote=Anonymous][quote=Anonymous][quote=Anonymous]Shield test's negativity (or &quot;specificity&quot;) rate is 98.9%, according to themselves (slide 4):  https://www.iasaedu.org/cms/lib/IL01923163/Centricity/Domain/4/SHIELD%20IL%20IDPH%20overview%20050621.pdf

That means that the test correctly returns a negative result 98.9% of the time when the person is truly negative, and returns a &quot;false positive&quot; 1.1% of the time.

The Washington Post article posted earlier:

&quot;Rapid antigen and saliva PCR tests, which are frequently used in schools, [b]can have a false positive rate of 1 or 2 percent. That may sound low, but statisticians know that, when testing in a setting of low prevalence of disease, even a single-digit false-positive rate can be extremely problematic[/b].&quot;

This study uses a slightly less specific test (the BinaxNow rapid test), which has a specificity of 98.5% (https://abbott.mediaroom.com/2020-08-26-Abbotts-Fast-5-15-Minute-Easy-to-Use-COVID-19-Antigen-Test-Receives-FDA-Emergency-Use-Authorization-Mobile-App-Displays-Test-Results-to-Help-Our-Return-to-Daily-Life-Ramping-Production-to-50-Million-Tests-a-Month)

The ASM study shows that with a similar test specificity, and low PREVALENCE rates (0.1% to 1.0%), the percentage of positive tests that are false is between 60 and 94% (it's lower when the prevalence is higher).  https://asm.org/Articles/2020/November/SARS-CoV-2-Testing-Sensitivity-Is-Not-the-Whole-St

SO WHAT IS PREVALENCE DURING DELTA?

During delta and with twice weekly testing (so a lot of tests), [b]the UK found a prevalence rate in schools of 0.27% in primary schools [/b]and 0.42% in secondary schools in June, 2021.  Note that they didn't mask, and don't have vaccination approval for the 12-15 year olds.  They did of course do other mitigation measures related to the testing.  I offer this as it seems to be one of the only studies of PREVALENCE in schools, during delta, where there was lots of testing.  https://www.gov.uk/government/news/covid-19-study-finds-lower-prevalence-in-schools

[b]PREVALENCE outside of schools in the UK during early delta (June 24 to July 12) was 0.63%.[/b]  (https://www.medicalnewstoday.com/articles/covid-19-in-england-rising-infections-as-delta-variant-takes-hold#Delta-surge).

How does that PREVALENCE compare to covid CASE RATES (which is what we all obsessively look at in DC)?  Between June 24 and July 12, UK’s 7-day case rates per 100,000 went from 145 to 358 (https://coronavirus.data.gov.uk/details/cases).  In DC terms (of cases per day instead of 7 days) that is about 20/100,000 per day to 51/100,000 per day.

The point being that we likely have low prevalence + Probably even lower in schools as that's been true consistently + test has a specificity greater than 1%  = whole lot of false positives.
[/quote]

Sigh. Didn’t even look at this particular test’s specificity plus secondary testing by this lab as a mitigant for false positives. DC has actually entered into a pretty promising relationship here. Wish it was better publicized though. [/quote]

The particular tests specificity is literally cited above.

Wrong. Shield T3 is greater than 99% and they retest positives. The link to the actual site has been posted numerous times.

[/quote][/quote]

Further, we test for three genes present in COVID-19 (vs. one gene for some other tests), with a specificity of 99.8-99.9% and very, very few false positives.
https://www.shieldt3.com/shield-t3/frequently-asked-questions/
[/quote]

I'm PP asking for that, and thank you.[/quote]

NP. I just want to make sure everyone is looking at the correct data before people write off the test. It seems quite impressive. [/quote]

It does....but I'm worried about the conflict of the other statement (98.5% ) from the company and what's on the website.  Maybe the re-testing is what gets it up to the &gt;99%?  I want to hope this isn't just marketing.  Would be helpful if there was an FDA approval form, or something that showed some 'verifiable' analysis.[/quote]

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