There is no associated reference range for plasma glucose as the concentration should be assessed in conjunction with the fasting and diabetes status. Diabetes mellitus can be diagnosed based on random and fasting glucose. Various cut offs are quoted in the literature however the most commonly used are based on the WHO recommendations (2006) which states with symptoms of diabetes symptoms one requires:
• A random venous plasma glucose concentration ≥ 11.1 mmol/l or
• A fasting plasma glucose concentration ≥ 7.0 mmol/l (whole blood ≥ 6.1 mmol/l) or
• Two hour plasma glucose concentration ≥ 11.1 mmol/l two hours after 75g anhydrous glucose in an oral glucose tolerance test (OGTT).
Gestational diabetes should be diagnosed if the woman has either:
• A fasting plasma glucose level of 5.6mmol/l or above or
• A 2-hour plasma glucose level of 7.8mmol/l or above.