Today, CDC Director Dr. Walensky just stated PCR tests may stay positive for up to 12 weeks, well after people have commented on the test's high sensitivity.
There definitely is. My lab used a kit that checked for 3 genes. The CT should be normalized so that different kits should have similar sensitivity levels, however I think the CT count may depend on the kit, which would mean that there could be a lot of inconsistencies and heterogeneity among different kits.
The comment is likely directed at biotech companies who will report their own results to the FDA as a way to grant EUA approval. Most institutions don't approve of in-house validation because you can really report anything as being good. In order to prevent a company from saying their "contrived" results are good, which would provide them with an EUA, the FDA created their own validation method. The FDA knows what samples they provide are positive, as well as the limit of detection based on their serial dilutions. Therefore, if a company fails this form of validation it likely means that their PCR is flawed.
That's likely why you see many companies not reporting their results. Either they couldn't get results or they may have known that they falsified their in-house validation results and may be trying to obfuscate that fact.
I think this more indicative of the isolation question and the target genome being computer modeled based on Drosten's work. In other words the tests were not empaneled from and actual verifiable isolate of an actual infectious virus. I'm not necessarily saying it does not exist (I am open that assertion) simply because clearly the virus was not isolated to create the test. "since no isolates exist . . . ". That FDA document is in response to the question of isolation as I understand it.
Are there not multiple lab protocols - meaning one lab may use 1 or 2 genes or use different CT?
There definitely is. My lab used a kit that checked for 3 genes. The CT should be normalized so that different kits should have similar sensitivity levels, however I think the CT count may depend on the kit, which would mean that there could be a lot of inconsistencies and heterogeneity among different kits.
How 'bout commenting on the assay panel being "contrived". https://www.fda.gov/medical-devices/coronavirus-covid-19-and-medical-devices/sars-cov-2-reference-panel-comparative-data?fbclid=IwAR19B61CjjI72XBUtvTYd7c6eXUT9rQ5ifKpEXnrWp-h-EurWzQG9IoRCGU
The comment is likely directed at biotech companies who will report their own results to the FDA as a way to grant EUA approval. Most institutions don't approve of in-house validation because you can really report anything as being good. In order to prevent a company from saying their "contrived" results are good, which would provide them with an EUA, the FDA created their own validation method. The FDA knows what samples they provide are positive, as well as the limit of detection based on their serial dilutions. Therefore, if a company fails this form of validation it likely means that their PCR is flawed.
That's likely why you see many companies not reporting their results. Either they couldn't get results or they may have known that they falsified their in-house validation results and may be trying to obfuscate that fact.
I think this more indicative of the isolation question and the target genome being computer modeled based on Drosten's work. In other words the tests were not empaneled from and actual verifiable isolate of an actual infectious virus. I'm not necessarily saying it does not exist (I am open that assertion) simply because clearly the virus was not isolated to create the test. "since no isolates exist . . . ". That FDA document is in response to the question of isolation as I understand it.