A few folks have asked me to comment on this.
I do not think this is evidence of authorities admitting to qPCR failure.
It is evidence of them attempting to clean up the market ...albeit on very slow timetables.
Let’s review...
I do not think this is evidence of authorities admitting to qPCR failure.
It is evidence of them attempting to clean up the market ...albeit on very slow timetables.
Let’s review...
The FDA has circulated a set of control templates. They started this in May 2020 and more than a year later we are seeing the results.
Good that they are doing. Bad that it’s enforced over glacial time scales during a pandemic.
Good that they are doing. Bad that it’s enforced over glacial time scales during a pandemic.
What’s in the panel?
Not much.
C19 and MERs.
At various concentrations.
Not much.
C19 and MERs.
At various concentrations.
The varying concentrations are blinded and help the FDA measure the Limit Of Detection (LOD) for the tests.
What’s not in the templates and makes these LODs worthless?
Human DNA for the internal controls.
What’s not in the templates and makes these LODs worthless?
Human DNA for the internal controls.
If you measure your Viral LOD in absence of Human DNA, you get a fake a LOD as your primers will never see these conditions in reality.
Your primers may interact with human DNA and produce FP or FN as a result of this interference.
Your primers may interact with human DNA and produce FP or FN as a result of this interference.
Likewise some kits rightfully target human DNA to normalize the swab to swab variance of sample collection.
This is usually a competitive amplification where you PCR reagents are in competition for reagents and your viral LOD is usually weakened as the assay also amps human DNA
This is usually a competitive amplification where you PCR reagents are in competition for reagents and your viral LOD is usually weakened as the assay also amps human DNA
LoDs should be measured with and without internal controls because the number change when amplifying multiple targets in a multiplex format.
Already there are several kit providers that failed to deliver results. These providers should be avoided.
Already there are several kit providers that failed to deliver results. These providers should be avoided.
If they can’t simply run these over simplified controls from the FDA after a year of scalping the market with high prices, they are frauds.
I do not see TIbMolBio in the FDA list?
I do not see TIbMolBio in the FDA list?
Many asked why they are including flu.
This is a good idea.
You want both viruses targeted at the same time otherwise billing incentives screw this up.
Once a hospital gets a positive C19 test, they are not motivated to run a second test for influenza.
This is a good idea.
You want both viruses targeted at the same time otherwise billing incentives screw this up.
Once a hospital gets a positive C19 test, they are not motivated to run a second test for influenza.
In many hospitals, C19 has better reimbursement and lower liability than Flu patients. Once positive for C19, additional costs for follow on testing can only make reimbursement and billing more complicated.
Better to understand co-infections/cross talk in a single test.
Better to understand co-infections/cross talk in a single test.
This also pushes testing providers to more thoroughly measure their assay cross talk with other viruses.
You can see late CT cross talk with influenza in a ring test run in Australia.
Multiplex testing would clean this up.
health.gov.au/sites/default/…
You can see late CT cross talk with influenza in a ring test run in Australia.
Multiplex testing would clean this up.
health.gov.au/sites/default/…
In summary,
It’s good they are doing this.
It’s bad it’s done so slowly.
It’s irresponsible they only have 2 targets in the panel and doubly irresponsible they are measuring LOD, without human DNA present.
Have a look at the large Variance in LoDs per test (100x)
It’s good they are doing this.
It’s bad it’s done so slowly.
It’s irresponsible they only have 2 targets in the panel and doubly irresponsible they are measuring LOD, without human DNA present.
Have a look at the large Variance in LoDs per test (100x)
Perkin Elmer wins with 180 copies.
Quidel loses with 540000 copies.
Such low limits of detection creates False Negatives (FN).
Track and Trace is useless with such high FNs and test heterogeneity in the market.
Quidel loses with 540000 copies.
Such low limits of detection creates False Negatives (FN).
Track and Trace is useless with such high FNs and test heterogeneity in the market.
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