https://healthwise.punchng.com/pcr-based-covid-19-tests-may-give-20-false-negative-results-scientists/"
PCR-based COVID-19 tests may give 20% false negative results –ScientistsBy
Tessy Igomu
June 10, 2020
"New research carried out by a team of scientists from
Johns Hopkins School of Medicine, Baltimore, Maryland, United States of America, has revealed that Polymerise Chain Reaction-based COVID-19 tests may have a false negative rate of 20 per cent or more, depending on when it is done and when the sample is taken."
"In all, they identified seven studies that included data from 1,330 patient samples, including hospitalised patients and those managing their symptoms at home.
Their analysis showed that the likelihood of a false-negative result varied depending on the time since infection.
“It appears that the virus is not detectable immediately after infection.
“On the first day of infection, the probability of missing a diagnosis, i.e., a false-negative result was 100 per cent.
“At day 4 after exposure to the virus, the probability of a false-negative result seems to reduce to 67 per cent.
“By day 8, it decreases to 20 per cent, beginning to increase again afterwards. And by 3 weeks post-exposure, the chance of a false negative result reaches 66 per cent,” the authors estimated.
Explaining further, they said the results indicate that the virus is difficult to detect by RT-PCR in the days immediately following infection, suggesting that “this testing route offers limited value during 3–5 days of post-infection).”
The authors warned against taking major decisions, such as removing Personal Protective Equipment or ending quarantine, based on results obtained within the period
The researchers also noted that 8 days following exposure, which is calculated to be roughly equivalent to 3 days following the onset of symptoms, is the optimal time for testing.
“At this time, the risk of obtaining a false-negative result is at its lowest, although there is still a 1 in 5 chance of obtaining such a result,” they said.
The researchers stated further that the reasons for such a high rate of false negatives, beyond technique-associated error, include differences in the amount of viral genetic material in people’s samples and differences in sample collection techniques.
Based on their findings, the authors conclude that it is important to exercise caution when interpreting the results of RT-PCR tests for COVID-19, particularly if the test was done early in the course of infection.
If an individual has symptoms consistent with COVID-19 but tests negative, the authors suggest not ruling out infection and carefully considering the “clinical and epidemiologic situation.”____________________________
So what's the reason for Fauci's hysteria (and others gloming onto it) about getting everyone tested - as many people as possible -
when 20% to 100% of PCR tests return false negatives? Wouldn't that more indicate that there is no value or even a negative value to testing? Particularly if it is used to determine a course of treatment since the article quoted below suggests that
at day 4 there is still a 67% chance of a false negative, even though that is
getting toward the end of the narrow window to begin early intervention with anti-virals, for the most successful outcome.
https://www.covid-19forum.org/index.php?topic=18.0
