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CDC Says Possibly 'Less Than Half' Of Positive Antibody Tests Are Correct
forbes ^ | Updated May 26, 2020, 07:56pm EDT | Tommy BeerForbes Staff

Posted on 05/28/2020 4:19:54 AM PDT by RaceBannon

TOPLINE In updated guidance posted on its website over the weekend, the U.S. Centers for Disease Control and Prevention acknowledged an inability to accurately determine if individuals had been infected with Covid-19 via antibody tests; if the test is used in a population where prevalence is low, it's possible that "less than half of those testing positive will truly have antibodies."

(Excerpt) Read more at forbes.com ...


TOPICS: Culture/Society; Front Page News; Government; News/Current Events
KEYWORDS: antibody; antibodytest; cdc; covid19; error; socialdistancing; testing
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KEY FACTS There are two kinds of Covid-19 tests: molecular diagnostic tests, which can identify people with active infections, even when they have no symptoms, and antibody, or serology, tests, which indicate that a person was infected at some point in the past.

According to Christopher Farnsworth, an instructor of pathology and immunology at Washington University School of Medicine, "antibody testing is really helpful in monitoring how widely a virus has spread within a community. Such testing could help determine how many people have recovered from the virus, even if they never had symptoms."

Thus, antibody tests could potentially play a very important role if and when schools should reopen, or when professional sports will return.

However, the CDC has acknowledged that antibody testing can frequently be inaccurate, especially in populations where there is a low prevalence of the coronavirus.

In fact, under certain scenarios, “less than half of those testing positive will truly have antibodies,” the agency says.

This is particularly dangerous because it could lead to individuals believing they have been infected with the coronavirus, and acting as if they have immunity, when that is not the case.

1 posted on 05/28/2020 4:19:54 AM PDT by RaceBannon
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To: RaceBannon

there is something else, if you DO have antibodies, and test NEGative because it was wrong, yet you DO have antibodies, you will be singled out for mandatory isolation or ppe that you dont need!


2 posted on 05/28/2020 4:21:59 AM PDT by RaceBannon (Rom 5:8 But God commendeth his love toward us, in that, while we were yet sinners, Christ died for)
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To: RaceBannon

They’re talking about false positives.

If a test had a 50% false positive rate, I’d consider it worthless, and I think most others would to. For example, you could then test a population where absolutely no one had, or ever had, the virus and conclude that 50% had been infected and you were close to herd immunity.

How can the CDC say this?

Manufacturers have been claiming 95 to 99% accuracy. I’d say its extremely important to have some accuracy here.


3 posted on 05/28/2020 4:24:11 AM PDT by Pearls Before Swine
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To: Pearls Before Swine

How do you know that the concept of “herd immunity” exists for this virus?


4 posted on 05/28/2020 4:25:52 AM PDT by Jim Noble (Think like you’re right, listen like you’re wrong)
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To: RaceBannon
CDC Says Possibly 'Less Than Half' Of Positive Antibody Tests Are Correct

I can provide all the tests needed for 25 cents each and these test will be just as accurate.


5 posted on 05/28/2020 4:26:14 AM PDT by Flick Lives (My work's illegal, but at least it's honest. - Capt. Malcolm Reynolds)
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To: RaceBannon

We don’t know nothing ‘bout nothing, but we’d like to shut down a booming economy and disrupt millions of lives. We’re from the government, and we’re here to help you.


6 posted on 05/28/2020 4:28:32 AM PDT by ClearCase_guy (If White Privilege is real, why did Elizabeth Warren lie about being an Indian?)
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To: RaceBannon

Wait, so it would be more accurate if the results were flipped? I FU-—NG LOVE SCIENCE!!!


7 posted on 05/28/2020 4:29:57 AM PDT by cdcdawg ("Americanism, not Globalism, will be our credo." DJT 2016)
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To: Jim Noble
How do you know that the concept of “herd immunity” exists for this virus?

If prior exposure confers immunity, than it does. If people who have survived the virus can either be readily reinfected, or remain long term carriers, it doesn't.

So, the answer to your question is "I don't know, but many past infectious disease outbreaks have reached a herd immunity state."

But that wasn't the point of my original post. I think that either the CDC is being completely alarmist, in saying that half the tests are bad, which implies a 50% false positive rate. If they aren't, then the manufacturers are peddling very bad tests.

There is one other possibility that occurs to me, though. If you have a 5% false positive rate (a 95% accurate test, neglecting false negatives), and you say the population has 10% exposure, yes, you could be off by 50%. But that's not a very precise statistic--no herd immunity at 10%! Whether its 5% or 10% of the population that's been exposed, it doesn't alter policy considerations.

8 posted on 05/28/2020 4:32:20 AM PDT by Pearls Before Swine
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To: RaceBannon; DoughtyOne; Vermont Lt; gas_dr
If prior CoV infections produce cross-reacting antibodies with SARS CoV 2, then how do we know those "false" antibodies are not to some degree protective?

WE DON'T.

A paper is being published in Cell that claims that 34% of healthy non-COVID people carry memory T-cells that transform in the presence of SARS Co V 2 antigens.

Now, this is not a clinical paper. It's published by in vitro cell nerds in a pure science journal.

But if it's right, it's great news because it may explain some of the observed facts, like low risk of household transmission with wide confidence intervals (for example).

Lots of hot stuff beginning to appear, as the virus and the disease it causes come into sharper focus.

9 posted on 05/28/2020 4:34:41 AM PDT by Jim Noble (Think like you’re right, listen like you’re wrong)
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To: Pearls Before Swine

It is important to for the WHO and CDC to squash hopes of those who test positive for antibodies. If this test is valid, then you don’t need a vaccine. Trillions at stake here for the ghouls imprisoning the serfs until the vaccine (heavenly choir singing) that everyone must take and must be certified after elections.


10 posted on 05/28/2020 4:35:55 AM PDT by epluribus_2 (He, had the best mom - ever.)
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To: RaceBannon

The CDC is in the testing biz, too...

https://www.cdc.gov/coronavirus/2019-ncov/lab/serology-testing.html


11 posted on 05/28/2020 4:37:00 AM PDT by mewzilla (Break out the mustard seeds.)
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To: Pearls Before Swine

Is the CDC playing politics again?


12 posted on 05/28/2020 4:38:07 AM PDT by xzins (Retired US Army chaplain. Support our troops by praying for their victory.)
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To: RaceBannon

Any links to where it says this on the actual CDC.gov website? Thanks.. d:^)


13 posted on 05/28/2020 4:40:28 AM PDT by CopperTop (Outside the wire it's just us chickens. Dig?)
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To: RaceBannon

Close enough for government work.


14 posted on 05/28/2020 4:41:03 AM PDT by Flag_This (China delenda est.)
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To: RaceBannon

CDC-FauXi-SOROS-Xi-Gates make virus to murder humans
by the millions using HIV-covering the ACE-2
receptor taken from Pangolins into bat coronovirus.

They patent the whole thing including vaccines,
and the power to infect humans with HIV using the virus.
(and of course the USPTO sees UTILITY there).

Jan. 2020 - Pelosi and China release the virus
and the fake impeachment.

MSM complicit in TERROR 24/7

FauXi deems disease is diagnoses by .... symptoms.

Cases soar, and to really really stoke the fire
DNC governors SEED nursing homes with desease.

Today, riots in the streets orchestrated by
Soros, death vaccines prepared by CDC-WHO-Gates,
and the US Congress hides like the rats they are.


15 posted on 05/28/2020 4:41:16 AM PDT by Diogenesis ( WWG1WGA)
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To: Pearls Before Swine

I think CDC is saying that the rate of false positives can be high relative to the number of positives in a large sample of tests. For example, if 1% of a population has the virus, but the test has a false positive rate of 1%, then 2% of the people tested will get a positive result - those actually positive and the false positives. In this case 50% of the positives are false.
But if 20% of the population actually has the virus, an additional 1% false positive is only 1/21 of the total number of positives (less than 5% of the positives are false positives)


16 posted on 05/28/2020 4:44:03 AM PDT by brookwood (Obama said you could keep your plan - Sanders says higher taxes will improve the weather)
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To: brookwood

We’re saying the same thing.

Even a low false positive rate gives an exaggerated reading in a population with a low incidence of infection.

But emphasizing this seems misleading, doesn’t it?


17 posted on 05/28/2020 5:02:05 AM PDT by Pearls Before Swine
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To: RaceBannon

Given that it appears that less than half of what the CDC says is also incorrect, what’s the news here?


18 posted on 05/28/2020 5:03:17 AM PDT by Da Coyote
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To: RaceBannon

The CDC has become an agent of chaos. They keep “leaarning” something new, and then they change it. First, for instance, they had us all paranoid about getting the virus from touching surfaces, then they said such transmission was extremely unlikely, now they are back to catching the virus from hard surfaces is quite probable. And, after most of the states and businesses have setled on 6 feet separation, they say that six feet might not be enough and on the issue of ace masks, the virus droplets might hang in the air for hours so the masks will be ineffective if you walk through such a cloud. This all makes no sense unless they are just trying to destroy any confidence in the government, the economy, and the ability to go out at all.


19 posted on 05/28/2020 5:04:35 AM PDT by Truth29
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To: RaceBannon

That gerbil fauxci thinks we should stay locked down till no positive tests for virus found. I’d like my sink tap to spew 20 dollar gold pieces. Neither is going to ever happen.


20 posted on 05/28/2020 5:16:17 AM PDT by Mouton (The media is the enemy of the people.)
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