Once your blood sugar is over 10 then some sugar gets passed out through your kidneys, which is why one of the symptoms of undiagnosed diabetics is extreme thirst. Not sure how much that reduces your blood sugar, and remember that 10 is already above normal levels. When I was first diagnosed (1970) there were no glucometers so the only at home test was to do an at home chemistry experiment on a urine sample (5 drops urine, 10 drops water, add pill, shake test tube and wait to see what colour it goes to see the amount of sugar in the urine).I asked my Nurse could drinking loads of water flush the sugar out of my system i thought be easy way to get rid but was told you can't get the sugar out of your Blood once it's in only by exercise!!!![]()