Page 48 - Clinical Biochemistry 08PB804

WHO(1999)
Impaired glucose tolerance

• IGT is a pre-diabetic state of hyperglycemia that is associated with insulin resistance and
increased risk of cardiovascular pathology.

• IGT may precede type 2 diabetes mellitus by many years.
• IGT is also a risk factor for mortality.
Impaired fasting glycemia
• Impaired fasting glycemia (IFG) may also be known as pre-diabetes or metabolic
syndrome.

• Impaired fasting glycemia occurs when blood glucose levels in the body are elevated during
periods of fasting, but not enough to prompt a diagnosis of diabetes.

• Effectively, a person with impaired fasting glycemia isn’t able to process glucose as
efficiently as they should be able to.

HbA1c
• The term HbA1c refers to glycated haemoglobin.
• It develops when haemoglobin, a protein within red blood cells that carries oxygen
throughout your body, joins with glucose in the blood, becoming 'glycated’.

• By measuring glycated haemoglobin (HbA1c), clinicians are able to get an overall picture
of what our average blood sugar levels have been over a period of weeks/months.

Glucose Tolerance Test
 3 days of unrestricted diet and exercise
 Overnight fast of 8-14 hours

Test
 Fasting blood on the morning
 Drink 75g of anhydrous glucose in 250-300ml water over 5 mins
 Blood sample 2 hours later