5 ms·
It's unrealistic to use RT-PCR testing on the entire U.S. population to derive what is essentially a binary result. RT-PCR tests are too time consuming, too se
by johnohara 6y ago
It's unrealistic to use RT-PCR testing on the entire U.S. population to derive what is essentially a binary result.
RT-PCR tests are too time consuming, too sensitive, and too reliant on specialized laboratory equipment for that. Right now however, they are all we have to achieve results accurate enough for some form of certification.
Immunoassays are simpler, faster, localized, and less expensive, but may also yield positive results for other coronaviruses such as 229E, NL63, OC43, HKU1, SARS-CoV, and MERS-CoV.
Germany may be isolating potential COVID-19 positives by using immunoassays, then using RT-PCR to be certain. I don't know. But it doesn't mean those "negatives" will always remain so.
- beagle3 6y agoPlease correct me if I'm wrong, but rt-PCR can only detect active SARS-Cov-2 shedding - meaning active disease, whereas immuno-assays check for the existence of antibodies. A SARS-Cov-2 naive person will be negative to both; early on, rt-PCR will be positive[0] and immunoassay will be negative; then (if and when the immune system manages to synthesize the right antibodies) they will both be positive; then the virus is eradicated so rt-PCR will go negative, but the immunoassay will stay positive (for a while; unknown yet if for life) [0] Assuming perfect accuracy and specificity.
- johnohara 6y agoI agree with your reply. Thank you for it. The recent seroprevalence study performed in Santa Clara County [0] [1] used an immunoassay manufactured by Premier BioTech, Minneapolis, MN. Their page entitled "PCR And Serology Based Testing Explained" does a very good job explaining what we both understand [2]. I stand by my opinion that it is unrealistic to use RT-PCR testing on the entire U.S. population. It is too sensitive and too time-consuming given the time constraints we are under. This Wash Post article (printed by MSN) describes why the CDC had to recall its initial testing kits. [3] [0] https://www.medrxiv.org/content/10.1101/2020.04.14.20062463v1 https://www.medrxiv.org/content/10.1101/2020.04.14.20062463v... [1] https://news.ycombinator.com/item?id=22899272 https://news.ycombinator.com/item?id=22899272 [2] https://premierbiotech.com/innovation/pcr-and-serology-based-testing-explained/ https://premierbiotech.com/innovation/pcr-and-serology-based... [3] https://www.msn.com/en-us/news/us/contamination-at-cdc-lab-delayed-rollout-of-coronavirus-tests/ar-BB12Q90W https://www.msn.com/en-us/news/us/contamination-at-cdc-lab-d...