impaired fasting glycaemia (IFG)

Last reviewed 01/2018

  • this has been introduced to classify individuals who have fasting glucose values above the normal range but below those diagnostic of diabetes. (fasting plasma glucose >= 6.1 mmol/l but < 7.0 mmol/l)
  • the BDA recommends that all those with impaired fasting glycaemia (IFG) should have an oral glucose tolerance test to exclude the diagnosis of diabetes, and are actively managed with life style advice
    • the oral glucose tolerance test reveals a 2 hour result of <7.8 mmol/l (2)
  • the relative risk of progressing to diabetes for patients with IFG is 1.1-2.2% per year (1)
  • patients with IFG may also have manifestations of metabolic syndrome. There is also an increased cardiovascular risk associated with patients with IFG compared with people with fasting glycaemia in the normal range. Patients with IFG need to have their macrovascular risks assessed and the calculated risk increased because of their IFG - a doubling of risk to allow for increased risk has been suggested (1)
  • these people should be followed up annually to reassess glucose regulation and all other cardiovascular risk factors (3)


  • in the United States, the definition of IFG was changed to a fasting plasma glucose of 100-125 mg/dl (5.6-6.9 mmol/l) (4)


  1. Pulse 2004; 64 (6).
  2. MeReC Briefing 2004;25:1-8.
  3. JBS2: Joint British Societies' guidelines on prevention of cardiovascular disease in clinical practice. Heart 2005; 91 (Supp 5).
  4. Expert Committee on the Diagnosis and Classification of Diabetes Mellitus: Report of the expert committee on the diagnosis and classification of diabetes mellitus. Diabetes Care 26 (Suppl. 1):S5-S20, 2003.