But it is worth doing the experiment. Or for a pixel to be lost. A lot of radiation will do it. That is the electronics temperature. This can be sorted out from the pedestal.
Lets take the electronics drift first.
It will depend on how all the errors add up. Now the dark current. The square root of 2200 is 47 electrons. But we measure in ADU which is roughly 2.2 electrons. OK, it is never as easy as this.