04-01-2020, 09:30 PM
Take a look at https://www.nytimes.com/2020/04/01/well/...ative.html
The CDC test hast a negative control and a positive control for the overall test run in the PCR machine. Ir also has (at least in theory) a control to make sure the sample didn't get "lost" in the prep. I naturally have no idea what the "Chinese" test controls were. However, it is really, really important to realize the tests we are using, and that everybody else is using, while possibly different, have not been "validated". In the US they are approved on an emergency basis. We don't know what their sensitivity is. We don't know for sure that anybody with the disease will have adequate virus titers in the upper respiratory tract for the test(s) to detect it.
This is nobody's "fault". This is a novel virus. There were no calibration runs. If there is a 30% false negative (or worse) level, thank goodness we are treating everybody that has symptoms as if they were positive.
The CDC test hast a negative control and a positive control for the overall test run in the PCR machine. Ir also has (at least in theory) a control to make sure the sample didn't get "lost" in the prep. I naturally have no idea what the "Chinese" test controls were. However, it is really, really important to realize the tests we are using, and that everybody else is using, while possibly different, have not been "validated". In the US they are approved on an emergency basis. We don't know what their sensitivity is. We don't know for sure that anybody with the disease will have adequate virus titers in the upper respiratory tract for the test(s) to detect it.
This is nobody's "fault". This is a novel virus. There were no calibration runs. If there is a 30% false negative (or worse) level, thank goodness we are treating everybody that has symptoms as if they were positive.