I have an Accu-CHEK Model-GT that my end gave me 2-3 years ago. I have been having problems with the unit. The last month when I test I get an incorrect test - the results indicate a very low reading - between 20-35. I will immediately retest and I will get a completely different but good reading. This has been happening o a regular basis - sometimes twice a day. I test 4 time per day. Other times I have been receiving an error code - with plenty of blood.