The most baffling thing is not standardising CT values for RT-PCR tests. I have looked and I cannot even find how increasing CT values affect the false positive rate for the PCR testing. If my understanding is correct a single increment of CT essentially doubles the sensitivity of the test, so difference between CT value of 35 and 40 is 32 fold. CDC is suggesting CT value of 28 for detecting breakthrough infections a…
Do you have source for that claim? I tried to find that recommendation, but all I came up with, was this fact check [1]. According to the fact check the CDC did NOT change cycle threshold, and the thresholds used to decide if test result is positive, are not different for vaccinated and unvaccinated. The quoted 28 cycle threshold is apparently only used for deciding if a sample can be submitted for sequencing. [1] ht…
https://www.aacc.org/science-and-research/covid-19-resources...