Glucose serves as the main source of energy for the body and its levels are tightly regulated by a variety of hormones, of which insulin is perhaps the most well known. The absence of insulin (type 1 diabetes mellitus (DM)) or insensitivity/resistance to its activity (type 2 DM) are characterised by hyperglycaemic states that initiate micro- and macro-vascular disease. Hypoglycaemia is a common presentation of (neonatal) inborn error of metabolism, insulinoma, factitious or over-administration of exogenous insulin, states of cachexia and hypopituitarism.
Diagnosis of DM, impaired glucose tolerance or insulin resistance
Monitoring of established DM
Diagnosis of metabolic disorders, endocrine neoplasia and hypopituitarism
Over 4 weeks old, fasting 3-6 mmol/L
Fluoride oxalate (grey top)
2x random glucose >11.1 mmol/L: diagnostic of DM.
2x fasting glucose >7.0 mmol/L: diagnostic of DM.
Oral glucose tolerance test (OGTT) 2h postprandial >11.1 mmol/L: diagnostic of DM.
Fasting glucose <7.0 mmol/L AND 2h postprandial OGTT 7.8-11.1 mmol/L: impaired glucose tolerance.
Fasting glucose 6.1-6.9 mmol/L AND/OR 2h postprandial OGTT <7.8 mmol/L: impaired fasting glucose.