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
|Sample & container required||Fluoride oxalate (grey top)|
|Sample volume||0.5 mL|
|Turnaround time||1 day|
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 if available 2h OGTT <7.8 mmol/L): impaired fasting glycaemia
Fasting glucose 5.5-6.9 mmol/L: consider referral into the NHS Diabetes prevention programme.