The test consists of a period of fasting (usually overnight) and then testing for a blood sugar level (or fasting blood sugar level) in the morning. (jhackett_ra.tripod.com)
If you see it, please bring your dog in for blood testing. (thedrakecenter.com)
You can check it out yourself here but it may not be too good for your blood pressure and that's with having deleted the worst of the comments. (theleakyboob.com)