Hypos Hypos occur when your blood glucose falls too low. It is difficult to avoid hypoglycaemia completely where your diabetes is treated with insulin and, if your everyday blood glucose is fairly low, hypos may seem more of a risk.

Blood glucose levels in diabetes

Blood glucose levels

The glucose level in the blood rises after a meal. This rise is dependent on the type and quantity of food eaten. In someone without diabetes this rise can go up to about 7 mmols/L after a meal. The fasting level of blood glucose in the absence of diabetes is 3 - 5 mmols/L. However, when diabetes is present, the glucose level will always be high unless treatment is instituted. Maintaining blood glucose levels as near normal as possible is one of the main aims of managing diabetes. This is to ensure day to day well-being and reduced risk of acute and chronic complications. Blood glucose levels fluctuate on a daily basis due on food intake, activity levels and drug therapy such as oral hypoglycaemic agents or insulin.

Oral glucose tolerance test

The oral glucose tolerance test (OGTT) is a definitive test to diagnose diabetes. The OGTT identifies chronic high blood glucose levels or hyperglycaemia and is used when the random plasma range is uncertain. The patient is fasted from midnight for about 8 hours. A fasting venous blood sample is taken prior to oral glucose drink containing 75g of glucose. A further venous blood sample is taken 2 hours later. A result greater than 11.1 mmols/L confirms a diagnosis of diabetes.

Glucose in the urine

Glycosuria or the presence of glucose in the urine is commonly found when the level of glucose in the blood is high. However it is not a diagnostic test for diabetes due to the variability in renal threshold within and between individuals. Urine testing has been used as a screening tool for diabetes in the past but this is no longer encouraged due to its poor reliability and inaccuracy. Assessing glycaemic control has been superseded by blood glucose monitoring.

Blood glucose monitoring

Blood glucose monitoring is nowadays gold standard for assessing day to day glycaemic control. It is an important component of self-management and empowerment for patients. It enables the patient to have immediate information about the blood glucose level which can help direct behaviour changes such as treating a low level and maintaining safety or insulin dose adjustments. Self-testing is simple and all patients on suphonylureas or insulin should be taught to monitor their blood glucose levels with a hand-held blood glucose monitor.

Written by a Diabetes Specialist Nurse