![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
shadowkatOkay, I just read another post from a friend, last two had been from family members - describing the COVID-19 symptoms, and getting a negative test result. Each person described slightly similar symptoms. Severe muscle aches, headaches, rash, fatigue, fever, chills. The nasal swab came back negative for every one. They had the SAME symptoms.
Of the three, only one knows how they may have gotten it.
So I did a little checking. And I discovered four separate articles on false negatives in the testing from medical journals and science/medical related sites that were accurate.
1. From the Geisel School of Medicine in Dartmouth - New Report Challenges and Implications of False Negative-COVID-19 Tests
But according to a new Dartmouth-led paper published in the New England Journal of Medicine, more emphasis should be placed on addressing the inaccuracy of diagnostic tests, which play a key role in containing the pandemic.
"Diagnostic tests, typically involving a nasopharyngeal swab, can be inaccurate in two ways," explains lead author Steven Woloshin, MD, MS, a professor of medicine and community and family medicine at Dartmouth's Geisel School of Medicine, and of The Dartmouth Institute for Health Policy and Clinical Practice. "A false-positive result mistakenly labels a person infected, with consequences including unnecessary quarantine and contact tracing. False-negative results are far more consequential because infected persons who might be asymptomatic may not be isolated and can infect others."
In their paper, Woloshin and his colleagues discuss factors contributing to the current limitations of diagnostic tests—including variability in test sensitivity and the lack of a standard process for validating test accuracy—and also cite several large studies whose frequent false-negative results are cause for concern.
The researchers draw several conclusions from their work. "Diagnostic testing will help to safely open the country, but only if the tests are highly sensitive and validated against a clinically meaningful reference standard—otherwise we cannot confidently declare people uninfected," says Woloshin.
The FDA should also ensure that test manufacturers provide details of their tests' clinical sensitivity and specificity at the time of market authorization. Tests without such information will have less relevance to patient care.
"Measuring the sensitivity of tests in asymptomatic people is an urgent priority," says Woloshin. "A negative result on even a highly sensitive test cannot rule out infection if the pretest probability—an estimate before testing of a person's chance of being infected—is high, so clinicians shouldn't trust unexpected negative results."
This estimate might depend on how common COVID-19 is where a person lives, their exposure history, and symptoms, he says.
2. Beware False Negatives as a Diagnostic
Laboratory professionals across the U.S. and the globe have used RT-PCR to find out if a person has been infected with SARS-CoV-2, the virus that causes COVID-19. These tests have played a critical role in our nation's response to the pandemic. But, while they are important, researchers at Johns Hopkins have found that the chance of a false negative result—when a virus is not detected in a person who actually is, or recently has been, infected—is greater than 1 in 5 and, at times, far higher. The researchers caution that the predictive value of these tests may not always yield accurate results, and timing of the test seems to matter greatly in the accuracy.
In the report on the findings published May 13 in the journal Annals of Internal Medicine, the researchers found that the probability of a false negative result decreases from 100% on Day 1 of being infected to 67% on Day 4. The false negative rate decreased to 20% on Day 8 (three days after a person begins experiencing symptoms). They also found that on the day a person started experiencing actual symptoms of illness, the average false negative rate was 38%. In addition, the false negative rate began to increase again from 21% on Day 9 to 66% on Day 21.
The study, which analyzed seven previously published studies on RT-PCR performance, adds to evidence that caution should be used in the interpretation of negative test results, particularly for individuals likely to have been exposed or who have symptoms consistent with COVID-19.
My Aunt was tested on Day 30 and got a false negative. It took her three months to get past the worst of it, she's still recovering.
3. From Healthline - If You Have Symptoms Assume You HAVE COVID
4. Science Daily - False Negative Test Results if Too Early via John Hopkins University Study
In short, if you have the symptoms for COVID-19 and get tested, assume you have it regardless of the result. The tests are highly inaccurate. I was skeptical at first - but I've had too many people who are not associated with each other, and reliable, tell me their symptoms and that they got a negative test result. On top of this, a college friend related a story about a friend of theirs who had COVID and discovered that the accuracy of the tests was maybe 85% or less. It's not 100%.
This means, we don't really know the true infection rate. We just know how many are being hospitalized, released from hospitals, tested, how many positive tests there have been, died in the hospital. What we do not know is: how many actually have had it, how many had false negatives, how many died at home with it never hospitalized, and how many recovered from it without being tested (I know quite a few people who had it and weren't tested and recovered).
That means - social distance, wear masks, and handwash. It also means to be careful.
I do know from family members that sunshine and outdoors helps counteract the virus. They felt better when they were in the sunshine.
Of the three, only one knows how they may have gotten it.
So I did a little checking. And I discovered four separate articles on false negatives in the testing from medical journals and science/medical related sites that were accurate.
1. From the Geisel School of Medicine in Dartmouth - New Report Challenges and Implications of False Negative-COVID-19 Tests
But according to a new Dartmouth-led paper published in the New England Journal of Medicine, more emphasis should be placed on addressing the inaccuracy of diagnostic tests, which play a key role in containing the pandemic.
"Diagnostic tests, typically involving a nasopharyngeal swab, can be inaccurate in two ways," explains lead author Steven Woloshin, MD, MS, a professor of medicine and community and family medicine at Dartmouth's Geisel School of Medicine, and of The Dartmouth Institute for Health Policy and Clinical Practice. "A false-positive result mistakenly labels a person infected, with consequences including unnecessary quarantine and contact tracing. False-negative results are far more consequential because infected persons who might be asymptomatic may not be isolated and can infect others."
In their paper, Woloshin and his colleagues discuss factors contributing to the current limitations of diagnostic tests—including variability in test sensitivity and the lack of a standard process for validating test accuracy—and also cite several large studies whose frequent false-negative results are cause for concern.
The researchers draw several conclusions from their work. "Diagnostic testing will help to safely open the country, but only if the tests are highly sensitive and validated against a clinically meaningful reference standard—otherwise we cannot confidently declare people uninfected," says Woloshin.
The FDA should also ensure that test manufacturers provide details of their tests' clinical sensitivity and specificity at the time of market authorization. Tests without such information will have less relevance to patient care.
"Measuring the sensitivity of tests in asymptomatic people is an urgent priority," says Woloshin. "A negative result on even a highly sensitive test cannot rule out infection if the pretest probability—an estimate before testing of a person's chance of being infected—is high, so clinicians shouldn't trust unexpected negative results."
This estimate might depend on how common COVID-19 is where a person lives, their exposure history, and symptoms, he says.
2. Beware False Negatives as a Diagnostic
Laboratory professionals across the U.S. and the globe have used RT-PCR to find out if a person has been infected with SARS-CoV-2, the virus that causes COVID-19. These tests have played a critical role in our nation's response to the pandemic. But, while they are important, researchers at Johns Hopkins have found that the chance of a false negative result—when a virus is not detected in a person who actually is, or recently has been, infected—is greater than 1 in 5 and, at times, far higher. The researchers caution that the predictive value of these tests may not always yield accurate results, and timing of the test seems to matter greatly in the accuracy.
In the report on the findings published May 13 in the journal Annals of Internal Medicine, the researchers found that the probability of a false negative result decreases from 100% on Day 1 of being infected to 67% on Day 4. The false negative rate decreased to 20% on Day 8 (three days after a person begins experiencing symptoms). They also found that on the day a person started experiencing actual symptoms of illness, the average false negative rate was 38%. In addition, the false negative rate began to increase again from 21% on Day 9 to 66% on Day 21.
The study, which analyzed seven previously published studies on RT-PCR performance, adds to evidence that caution should be used in the interpretation of negative test results, particularly for individuals likely to have been exposed or who have symptoms consistent with COVID-19.
My Aunt was tested on Day 30 and got a false negative. It took her three months to get past the worst of it, she's still recovering.
3. From Healthline - If You Have Symptoms Assume You HAVE COVID
4. Science Daily - False Negative Test Results if Too Early via John Hopkins University Study
In short, if you have the symptoms for COVID-19 and get tested, assume you have it regardless of the result. The tests are highly inaccurate. I was skeptical at first - but I've had too many people who are not associated with each other, and reliable, tell me their symptoms and that they got a negative test result. On top of this, a college friend related a story about a friend of theirs who had COVID and discovered that the accuracy of the tests was maybe 85% or less. It's not 100%.
This means, we don't really know the true infection rate. We just know how many are being hospitalized, released from hospitals, tested, how many positive tests there have been, died in the hospital. What we do not know is: how many actually have had it, how many had false negatives, how many died at home with it never hospitalized, and how many recovered from it without being tested (I know quite a few people who had it and weren't tested and recovered).
That means - social distance, wear masks, and handwash. It also means to be careful.
I do know from family members that sunshine and outdoors helps counteract the virus. They felt better when they were in the sunshine.
no subject
Date: 2020-06-26 03:48 pm (UTC)The antibody tests have been getting better over the last months. I only took it, when a lab I knew the head of, had a proper one. But yeah, they are not entirely trustworthy either. But doing two tests significantly increases the chance of catching it in one of them.
no subject
Date: 2020-06-26 05:00 pm (UTC)The difficulty is that there's so much out there already. There's thousands of coronaviruses out there, this is just the newest one and it has no vaccine and is highly contagious.NL95 or NL93, can't remember precise name, is out there too, it's a respiratory virus, which has a vaccine and isn't that bad.
And of course AIDs. Actually COVID-19 and how people are responding to it, reminds me a bit of AIDS, but on a much larger scale.
I don't think either of us have had it.