The diagnosis of diabetes mellitus, including gestational diabetes

Fasting plasma glucose as a diagnostic indicator of diabetes mellitus

Among 233 patients referred for glucose tolerance test (GTT), 36.4% of 129 non-pregnant subjects were classified as diabetic, compared with only 2.9% of 104 pregnant subjects. Preliminary screening using a fasting plasma glucose upper cut-off of 7.0 mmol/l, above which the subject was classified as diabetic and a lower one of 4.4 mmol/l, below which he or she was considered normal, would have eliminated the need for 30% of GTTs and positively identified 60% of the diabetics in the non-pregnant group. Only one patient would have been significantly misclassified, possibly owing to inadequate fasting. However, little benefit would result from applying an upper cut-off to low-prevalence populations such as the pregnant group. Like other recent surveys, this study suggests that World Health Organisation diagnostic figures for fasting plasma glucose could be revised downwards to 7.0 mmol/l. Conversely, to be fairly certain that an individual is not diabetic, fasting plasma glucose must be below about 4.4 mmol/l.

Blood and urine tests for diagnosis and monitoring of diabetes

The diagnosis of diabetes is made on the evidence of raised blood glucose levels. In diabetic patients, regular monitoring of blood and urine guides decisions about treatment and helps to minimise the risk of complications. This article describes various diagnostic tests that can be used both in the laboratory and outside.

Diabetes in childhood

Insulin-dependent diabetes mellitus is the most common endocrine disorder of childhood. Early diagnosis is important. A multidisciplinary team approach enables families to assume responsibility for self-management. The paediatric diabetes nurse specialist is a key member of the team.