No Title
Something extremely bogus is going on. Was tested for covid four times today. Two tests came back negative, two came back positive. Same machine, same test, same nurse. Rapid antigen test from BD.
If you are not familiar with the Covid-19 PCR testing methodology, you should become so.
most commonly used coronavirus tests in America are polymerase chain reaction tests, or PCR tests. According to Mandavilli, PCR tests provide a yes or no answer to whether a patient is infected with the novel coronavirus.
…According to Mandavilli, PCR tests look for genetic matter from the new coronavirus using amplification cycles. The fewer cycles needed to detect genetic matter from the virus, the higher a patient’s viral load and the more likely that person is contagious, Mandavilli reports.
However, the number of amplification cycles that was needed to detect genetic matter from the virus, which is referred to as the cycle threshold, typically isn’t included in test results sent to doctors and patients, Mandavilli reports.
Mina said that information is more telling, as it indicates a patient’s viral load, and patients carrying minuscule amounts of the virus may not be contagious. Therefore, information on a patient’s viral load should be used to determine the patient’s next steps, Mina said.
“It’s really irresponsible, I think, to forgo the recognition that this is a quantitative issue,” he added.
But further complicating the matter, according to some experts, is that many commonly used tests for the novel coronavirus are too sensitive, so they generate positive results when patients are carrying low loads of the virus, Mandavilli reports.
According to Mandavilli, many coronavirus tests have fairly high cycle thresholds, with most set at 40 and some set at 37. That means a number of patients who aren’t carrying much of the new coronavirus are still testing positive, even though they may not be contagious, Mandavilli reports.
Mina explained that tests with high cycle thresholds could be detecting genetic fragments of the virus, or pieces of the virus that are leftover from a previous infection that don’t pose any current transmission risk.
Juliet Morrison, a virologist at the University of California-Riverside, said she believes any test with a cycle threshold over 35 is too sensitive. “I’m shocked that people would think that 40 could represent a positive,” she said.
And according to Mandavilli, a review conducted by the New York Times of three sets of coronavirus testing data from Massachusetts, Nevada, and New York found that up to 90% of patients in those data sets who tested positive for the coronavirus had very low viral loads.
Ashish Jha, director of the Harvard Global Health Institute, said of the Times review’s results, “I’m really shocked that it could be that high—the proportion of people with high [cycle threshold] value results.” He added, “Boy, does it really change the way we need to be thinking about testing.”
No Title
Elon Musk: I Got A COVID Test Four Times In One Day. ‘Two Came Back Negative, Two Came Back Positive.’ https://t.co/YTDxMjczMC pic.twitter.com/iT6DiveKP1
https://www.advisory.com/daily-briefing/2020/09/01/covid-tests