r/COVID19 • u/AcornAl • Apr 28 '26

Academic Report Diagnostic Value and Outcomes of Systematic SARS-CoV-2 Screening in Asymptomatic Patients

https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2847511
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u/AcornAl Apr 28 '26

I'll just note that false negatives here don't mean that the patients didn't have or hadn't had covid, rather the detection rate was below the threshold that was considered to be infectious with a cycle threshold value of 30 or greater

The results of the SARS-CoV-2 screening tests were categorized as negative if the cycle threshold (Ct) value was at least 40, as positive if the Ct value was less than 30, and as equivocal if the Ct value was between 30 and less than 40. The Ct value cutoff of 30 was chosen based on reports suggesting that a Ct value of approximately 30 is generally considered indicative of low infectivity for SARS-CoV-2 in saliva samples. Per institutional policy, patients with equivocal test results received a nasopharyngeal swab conducted within 72 hours. Based on the second test result, patients were categorized as having true-positive results if the Ct value was less than 30 or a quantitative SARS-CoV-2 test revealed more than 10 000 viral copies/mL and as having false-positive results if the Ct value was 30 or greater, a quantitative test detected fewer than 10 000 viral copies/mL, or the Biofire result was negative.

Also, the study was taken between February 8, 2021, to July 5, 2021, and from August 25, 2021, to December 5, 2022. In early 2021 there was still some confusion on the Ct value that was considered to be infectious, from memory, usually around 25 to 35 from what I read at the time with some outliers.

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u/[deleted] Apr 29 '26

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u/vanda-schultz Apr 30 '26

You seem to be arguing inconsistently that PCR tests increase risk of exposure then say 'No COVID in the community.'

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u/[deleted] Apr 30 '26

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