But they were not found to shed viruses.
Mystery in Wuhan: recovered coronavirus patients test negative then positive
11–20 of 123 posts
Re: Mystery in Wuhan: recovered coronavirus patients test negative then positive
#12Earlier quoted context omitted.
In general PCR tests are highly sensitive. Even smallest viral loads can be detected (Edit) added in general above due to valid points in the comments below
if: - you do them right - your reagents are good - the kit was assembled properly - there's no contamination in the machines - you got a good sample - ... The capability for a highly sensitive and accurate test in no way guarantees that a randomly sampled administration of that test is going to meet the high standard that the test may be capable of.
And if you swabbed an infected part of the body in the first place!
In 205 patients with proven COVID-19 [...] bronchoalveolar lavage fluid was positive in 14/15 (93%), sputum 75/104 (72%), nasal swabs 5/8 (63%), brush biopsy 6/13 (46%), pharyngeal swabs 126/398 (32%), feces 44/153 (29%), blood 3/307 (1%), and urine 0/72 (0%).
https://www.jwatch.org/na51116/2020/03/17/pharyngeal-and-nas...
Re: Mystery in Wuhan: recovered coronavirus patients test negative then positive
#13Literally false positive and false negatives. In other words, if you test millions of people, there will be more people tested positive who DON'T have the disease vs. those who test positive and HAVE the disease.
Re: Mystery in Wuhan: recovered coronavirus patients test negative then positive
#14Czechia got some quick tests from China. Their reliability was about 60% compared to lab, false positives and false negatives. I think DNA and RNA research is severely lacking in most countries. In a few years we will look at this year as 1960ies of computer engineering. Edit: source https://www.irozhlas.cz/zpravy-domov/ostrava-rychlotesty-kor...
Initially skeptical on your first claim but did find a source:
https://www.businessinsider.com/coronavirus-spain-says-rapid...
(https://outline.com/uBBJvY)
Re: Mystery in Wuhan: recovered coronavirus patients test negative then positive
#15Don't believe anything that comes out of China
Re: Mystery in Wuhan: recovered coronavirus patients test negative then positive
#16Czechia got some quick tests from China. Their reliability was about 60% compared to lab, false positives and false negatives. I think DNA and RNA research is severely lacking in most countries. In a few years we will look at this year as 1960ies of computer engineering. Edit: source https://www.irozhlas.cz/zpravy-domov/ostrava-rychlotesty-kor...
Initially skeptical on your first claim but did find a source: https://www.businessinsider.com/coronavirus-spain-says-rapid... ( https://outline.com/uBBJvY )
Sounds like a test from a single Chinese company and the results were closer to 30% accurate:
> The Chinese Embassy in Spain said that the Bioeasy tests were not part of China's medical donations and that the firm didn't have a license to sell its products.
Re: Mystery in Wuhan: recovered coronavirus patients test negative then positive
#17Earlier quoted context omitted.
The article mentions RNA implying that this is the PCR test not an Antibody test. False positives exist with the PCR test. Information I could find suggests the primary cause is sample contamination. So running the test multiple times through different labs and clinicians is an obvious workaround.
Surely this is not a false-positive, but rather a false-negative? That is, the patients were observed clinically to have caught and recovered from the virus, yet the test shows no trace of the viral infection.
> Surely this is not a false-positive, but rather a false-negative?
Both are possible and either mess it all up.
Re: Mystery in Wuhan: recovered coronavirus patients test negative then positive
#18[deleted]
Re: Mystery in Wuhan: recovered coronavirus patients test negative then positive
#19Earlier quoted context omitted.
Initially skeptical on your first claim but did find a source: https://www.businessinsider.com/coronavirus-spain-says-rapid... ( https://outline.com/uBBJvY )
Sounds like a test from a single Chinese company and the results were closer to 30% accurate: > The Chinese Embassy in Spain said that the Bioeasy tests were not part of China's medical donations and that the firm didn't have a license to sell its products.
30% accurate? Does that mean it's better to believe the opposite of what the test says most of the time?
Re: Mystery in Wuhan: recovered coronavirus patients test negative then positive
#20Earlier quoted context omitted.
In general PCR tests are highly sensitive. Even smallest viral loads can be detected (Edit) added in general above due to valid points in the comments below
The PCR can detect if there is virus in the swab. But the swab may not have scooped up any virus even though the person had some.
That’s right!