Pulling together all the info we have on Florida's new requirement that labs report cycle thresholds for COVID tests:
1/10
https://twitter.com/jhaskinscabrera/status/1335003879952539648?s=20
1/10
I don't expect this information to be public, but I would love to be wrong about that.
5/10
5/10
And this is based on a conversation with a single lab, but my understanding is that PCR instruments run doubling cycles and check after each cycle whether the amount of material has surpassed a level of detection. When it does, that number is stored in the machine.
6/10
6/10
That number is then compared to a reference scale to determine whether the sample is positive. For example, many tests have an "inconclusive" range, and they run the test again if the result is in that range.
7/10
7/10
In most cases, that number is not reported with the +/- result and is eventually wiped. This memo requires labs to start reporting it to FDOH. As explained in the Rational Ground article above, results with a lower number of cycles are more likely to be infectious.
8/10
8/10
It is unclear what FDOH will do with this information, but it is widely understood that setting the threshold for a positive test too high (as is currently the case) results in quarantining people who are not contagious.
9/10
9/10
So this may be the first step toward setting a new threshold for quarantining and contact tracing.
10/10
10/10
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