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Posted On: 05/13/2020 9:43:46 PM
Post# of 9144
False Negatives Raise More Questions About Virus Test Accuracy (Bloomberg)
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The first study found that Abbott’s ID NOW machine missed at least one-third of positive cases detected with a rival test, and as many as 48% when using the currently recommended dry nasal swabs, according to the report on BioRxiv
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The second analysis, published in the Annals of Internal Medicine and authored by Johns Hopkins researchers, analyzed seven previously-published studies evaluating 1,330 patient samples and focused on a group of widely-used Covid-19 diagnostic tests known as “polymerase chain reaction” tests. It suggested that false negatives are especially likely before the onset of symptoms, such as when a patient is tested soon after exposure to the virus.
When patients were tested immediately after infection, typically before symptoms occur, the false-negative rate was 100%. On the first day of symptoms, the false-negative rate was 38%. After three days of symptoms, false-negatives dropped to 20%. The rate began getting worse after five days, suggesting a narrow window for the most accurate results.
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https://www.bloomberg.com/news/articles/2020-...f=5sXCNkPB
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The first study found that Abbott’s ID NOW machine missed at least one-third of positive cases detected with a rival test, and as many as 48% when using the currently recommended dry nasal swabs, according to the report on BioRxiv
...
The second analysis, published in the Annals of Internal Medicine and authored by Johns Hopkins researchers, analyzed seven previously-published studies evaluating 1,330 patient samples and focused on a group of widely-used Covid-19 diagnostic tests known as “polymerase chain reaction” tests. It suggested that false negatives are especially likely before the onset of symptoms, such as when a patient is tested soon after exposure to the virus.
When patients were tested immediately after infection, typically before symptoms occur, the false-negative rate was 100%. On the first day of symptoms, the false-negative rate was 38%. After three days of symptoms, false-negatives dropped to 20%. The rate began getting worse after five days, suggesting a narrow window for the most accurate results.
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https://www.bloomberg.com/news/articles/2020-...f=5sXCNkPB
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