How credible are the test results for COVID-19? What are the False Negative rates of the testing kits used currently? Is it another ticking time bomb?
Thanks. However, false negatives still are a major concern. What do you think?
The current estimates of numbers of COVID-19 cases and deaths are very inaccurate. The sensitivity and specificity of the diagnostic tests for COVID-19 are not yet known in vivo. There are reports of very high sensitivity and specificity in vitro. However a number of confounding factors (e.g. the stage of illness and the way the swab was taken) mean that the false negative rate of these tests may be high in clinical practice.
Wenling Wang; Yanli Xu; Ruqin Gao; et al Detection of SARS-CoV-2 in Different Types of Clinical Specimens. Jama 2020 (in press).
The numbers of cases reported will also depend on strategies used for screening. Many countries are only screening symptomatic patients presenting to healthcare facilities. Others are attempting to screen a significant proportion of the population.
I believe the total number of cases of COVID-19 is significantly higher than that being reported. There are many confounding factors (both political and diagnostic) that make the initial number of deaths reported as being due to COVID-19 extremely difficult to interpret.
I believe retesting the recovered patients twice or thrice would significantly help to minimise the risk that arises out of false negatives.
Article Temporal profiles of viral load in posterior oropharyngeal s...
This may provide some clues to your questions
Please also take reference to the following:
Performance of VivaDiag COVID‐19 IgM/IgG Rapid Test is inadequate for diagnosis of COVID‐19 in acute patients referring to emergency room department.
J Med Virol.
doi:10.1002/jmv.25800
Early research indicates that a common test for COVID-19 may produce “false negatives” up to 30 percent of the time.Experts say the inaccuracies are probably caused by the collection of samples, not the actual laboratory testing.
The most common form of test used for COVID-19 is a molecular test known as a reverse transcriptase polymerase chain reaction (RT-PCR) test.The notion is that this is a virus that likes to implant itself on the mucous membranes high up in the back of the throat behind the nose. Swab have to put , not at the front of the nose, but rather far back. We can have a false negative if you have very little virus up there or perhaps the specimen was taken inappropriately or It didn’t get up high enough to actually get to the place where the virus was located.
https://www.researchgate.net/deref/https%3A%2F%2Fasm.org%2FArticles%2F2020%2FApril%2FFalse-Negatives-and-Reinfections-the-Challenges-of