Hi there...there is a chance of that happening. But there is also a small chance of technical error occurring. So when ever you get your test done, try to get it done at the same centre. Also fasting blood sugar is not he only parameter to check your diabetic status. You will have to get fasting booed sugar, post prandial blood sugar and HbA1C levels also checked. The last parameter is very important as it will show how well your sugars have been under control in the last 3 mths. Get all these tests done and consult a general physician. They will educate you about your diabetic status. Also diabetes is a life long disease. It requires life long treatment based on its severity, from exercising to diets to oral medications to insulin injections.