regarding your post just this week l had problems with my meter which was giving me very high readings and intially my gp was adjusting my insulin in accordance with these l felt terrible for a week ,my gp then came to the conclusion my meter had been faulty ,as these high readings were going from 24.7 and down to 16. 2 within minutes ,l emailed meter company who supplied this and told them ,with the result l spent 1 hour on the phone answering a whole range of questions ,the outcome is the company now have to carry out an official report regarding this as its a medical device.and because my insulin was adjusted round those faulty readings causing me to be ill.the company were relly nice though and have gave me replacement meter free of charge ,and my diabetes nurse replaced the one l had .so now if l have any doubts l can do comparasons between both meter readings,the lady from the company told me the ratio between reading was 31.6 percent which was well over the 15 ,indicating a fault problem ,she said they work this out with the readings.hope this helps ,