The level is the amount of glucose (sugar) in the blood. It is also known as serum glucose level. It is expressed as millimoles per litre (mmol/l).
Normally, stay within narrow limits throughout the day: 4 to 8mmol/l. But they are higher after meals and usually lowest in the morning. In diabetes the level moves outside these limits until treated. Even with good control of diabetes, the blood sugar level will still at times drift outside this normal range. | 
