“Fasting glucose 6.66” generally refers to fasting blood glucose 6.66mmol/L. Fasting blood glucose 6.66mmol/L is high and abnormal for normal people; for diabetic patients it is within the target range and normal. Due to different examination methods and reagents, the reference indexes of each hospital are different and need to be analyzed specifically. 1. The normal value of fasting blood glucose for normal people is between 3.9~6.1mmol/L, so fasting blood glucose of 6.66mmol/L is on the high side, and it is recommended to consult a professional physician for a clear diagnosis. 2. For patients who have been diagnosed with diabetes, fasting blood glucose should be controlled between 4.4~7.0mmol/L, so fasting blood glucose of 6.66mmol/L can reach the control target, and can continue the current treatment program. If abnormal blood glucose levels are detected during routine medical checkups, it is recommended to go to a regular hospital to avoid delays.