Changing Covid testing requirements
- Thread starter Kimela
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Of course that would be ideal, but that doesn't necessarily mean he is listening to the correct information sources. To flatly state that rapid testing is worthless is opinion stated as fact and is at odds with the best information I have been able to find. I do not believe that the data will back him up.
There are numerous articles highlighting if you test positive with a rapid test it is typically 2-5 days after your highest viral load and typically asymptomatic at that point. The PCR test would have you positive while showing symptoms. Here is one article, but there are plenty more. The pre print study is interesting.
Why rapid COVID tests aren't more accurate and how scientists hope to improve them
Recent research and anecdotes suggest some people are testing negative on rapid tests even after they have symptoms, then later testing positive. Here's what researchers think is going on.
www.npr.org
There are, I believe just two (not numerous) primary sources suggesting antigen tests for Covid might give a false negative in that 2-3 day period between infection and symptoms. The "numerous" comes from people citing and elaborating and extrapolating what the studies actually showed. Neither of the studies has been peer-reviewed, and only pre-prints are available. It is a bit soon to say the question is closed and antigen tests are worthless.There are numerous articles highlighting if you test positive with a rapid test it is typically 2-5 days after your highest viral load and typically asymptomatic at that point. The PCR test would have you positive while showing symptoms. Here is one article, but there are plenty more. The pre print study is interesting.
Why rapid COVID tests aren't more accurate and how scientists hope to improve them
Recent research and anecdotes suggest some people are testing negative on rapid tests even after they have symptoms, then later testing positive. Here's what researchers think is going on.
The current CDC guidance says:
"The sensitivity of antigen tests vary, but antigen tests are generally less sensitive than most laboratory-based NAATs. The antigen level in specimens collected either before symptom onset, or late in the course of infection, may be below these tests’ limit of detection. This may result in a negative antigen test result, while a more sensitive test, such as most NAATs, may return a positive result. Studies have shown that antigen tests have comparable sensitivity to laboratory-based NAATs when viral load in the specimen is high and the person is likely to be most contagious."
and"Positive and negative predictive values of all in vitro diagnostic tests (e.g., NAAT and antigen tests) vary depending on the pretest probability. Pretest probability considers both the prevalence of the target infection in the population that is being tested as well as the clinical context of the individual who is being tested. If the prevalence of infection in the community is high, and the person being tested is symptomatic, then the pretest probability is generally considered high. If the prevalence of infection in the community is low, and the person being tested is asymptomatic and has not had close contact to a person with COVID-19, then the pretest probability is generally considered low. See CDC’s Interpreting Results of Diagnostic Tests for additional information on the relationship between pretest probability and the likelihood of positive and negative predictive values."
This does not say antigen tests are worthless, only that they need to be used with care, especially if the prevalence of Covid in the population being tested is high, and the clinical context of the individual being tested is indicative, such as showing symptoms.
“Tromberg says a single negative test might make you feel better about running to the store with a mask on, or meeting a healthy friend for lunch. But if you're using it to decide if it's safe to visit your grandmother at the nursing home, don't rely on a single test alone, he says.
"If I'm going to the nursing home on Saturday, I would start to isolate and reduce my social contacts in the preceding week, and I would take a couple of tests," he says.”
Basically it is saying you can’t rely on the results and to keep testing until you get a positive or get a PCR test. How is that reliable? Especially witn omicron which the 2nd half of the article addresses. Totally very little has gone through appropriate peer reviews, it is a changing dynamic.
I started to look into this because I had symptoms for a week and tested negative each day. My vaccinated daughter then started symptoms and tested positive. I was then asymptomatic. She is vaccinated but only 8 so no booster. Once I started researching it, it became clear that false negatives are very common especially with symptoms.
My point is the tests aren’t reliable especially if you are concerned with transmitting it to others.
It's worthless for you to say it's worthless for him to say it's worthless. Although some might say it's worthless for me to say it's worthless for you to say it's worthless for him to say it's worthless. And still, it's worthless. that...
Your anecdotal account notwithstanding, "reliability" is a relative term; like everything else concerning COVID it is a matter of probabilities, and new information is constantly coming in. For a test to be worthless its reliability would have to be on the order of 50% (i.e., wrong as often as right). Rapid testing may not be 100% (nothing is) but it is much better than 50%.
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