Hi John,
Here is a link to a dark taken under the same conditions as yours using my ATIK 428. This camera is identical except for using a smaller version of the same CCD so should be a direct comparison.
https://drive.google.com/file/d/1QkocrvkQRBCOlTK9NbxOhSVxWMwM7COg/view?usp=sharing
If you have ISIS, it includes a nice feature which you can use to calculate the gain, and noise figures described here
http://www.astrosurf.com/buil/isis/noise/result.htm
These warm pixels are not specifically measured using this technique though. To get the dark current figures quoted by ATIK and measured by Christian Buil, you have to chose a measured area free of warm pixels.
Robin