Diagnosing diabetes & complications

Diagnosing Diabetes

To be able to decide on the appropriate treatment options for people with elevated blood glucose levels, specific diagnostic criteria have been devised. These guidelines and recommendations produced by the World Health Organisation (WHO) (9&10) and supported by Diabetes UK (8) are summarised in the table below.

The guidelines for diagnosing gestational diabetes were recently reviewed and updated by NICE and the new diagnostic criteria can also be seen in the table below (11).

Criteria Diagnosis


If diabetes control is not optimised there may be short-term and long-term complications.

Short-term complications:


Long-term complications:

The risk of certain micro- and macro-vascular complications (damage to small and large blood vessels) increases in those living with diabetes and with persistently high blood glucose levels (see table below). However, managing diabetes appropriately and optimising control can reduce the risk of these occurring and it is therefore important to maintain positivity and motivation to achieve the desired targets.

Microvascular 1


These are a general guide for adults with diabetes and may differ according to individual circumstances. You should always check with your healthcare team what you personal levels and targets are so you know what to aim for.

Capillary Blood Glucose

Not everyone will need to monitor their blood glucose on a daily basis, this is very individual and likely to depend on medical treatment. However, for those who do monitor, a good aim is:

  • fasting (before meal) blood glucose level = 4-7 mmol/l (12&13)
  • 2 hour post-meal blood glucose level = 5-9 mmol/l (12&13)

It is not expected that these blood glucose targets should be achieved 100% of the time, however if persistently out of target, a review of diet and medication is recommended.


  • 48-53mmol/mol (12,13&14)
  • <58mmol/mol if risk of severe hypoglycaemia (13)

Blood pressure

  • <140/80 mm Hg(14)
  • <130/80 mm Hg if kidney, eye, cerebrovascular damage  (14)

Cholesterol & Triglyceride levels

  • Total Cholesterol  = <4mmol/l (13)
  • LDL Cholesterol <2mmol/l (13)
  • HDL cholesterol ≥1mmol/l (men),  ≥1.2mmol/l (women)   (13)
  • Triglyceride = <1.7mmol/l (13)