Summary of replies

This is a brief summary of results of a very complicated audit. If you require a more detailed summary please email me This e-mail address is being protected from spambots. You need JavaScript enabled to view it

• Very wide range of values for fasting and random glucoses were given:
• Lower limit of “normal” fasting glucose range 2.0 – 3.9 mmol/l
• Upper limit of “normal” fasting glucose range 5.5 – 6.0 mmol/l
• Several labs had an “impaired fasting glycaemia” range of 6.1 – 6.9 mmol/l (one lab 5.6 – 6.9 mmol/l)
• Most labs stated that at fasting glucose >6.9 mmol/l was consistent with DM (one lab gave a value of > 7.0 mmol/l)
• A range for random glucoses was given by 8 labs. The values ranged from 2.2 to 11.0 mmol/l

• Fasting glucose < 6.0
• Random glucose < 7.8
• All inpatient and A&E glucose
• Glucose >2.9 (Specialist laboratory)
• Depends on who is validating and glucose results seen
• Random glucose < 11.1
• Glucose inside ranges quoted
• glucose < 20 known diabetics results > 2.0
• fasting glucose < 6.0
• random glucose < 6.0
• non fasting glucose sample
• inpatient glucose < 11.0

• 1 lab provided their comment (see below):-
• “WHO/ADA guidelines in a non-pregnant patient who is NOT ACUTELY ILL, DM is indicated by a confirmed fasting plasma glucose
• >6.9 mmo/l and is unlikely at a plasma glucose <5.6 mmol/l.
• In acute illness, interpretation of plasma glucose can be difficult. Please contact Clinical Biochemistry if advice is required. NB: Any comments assume that the patient is NOT a known diabetic or on any treatment that might affect the plasma glucose”.

• 2 hr post prandial
• 2 hr glucose

• At what level of glucose if any do you consider diabetes to be excluded?

• Most labs stated that DM was unlikely rather than excluded at the level they used.

• “Diabetes unlikely” fasting glucoses <5.0 mmol/l to < 7.0 mmol/l

• “Diabetes unliley “random glucose level values ranged from

• <5.5 - < 11.0 mmol/l

• 10 labs fasting glucose 6.0 – 7.0 mmol/L
• - 2 labs require a glucose at this level on 2 occasions
• 2 labs fasting glucose > 5.5 – 7.0
• 1 lab random glucose > 7.2 mmol/l
• 1 lab not currently recommending GTTs because of waiting time
• 1 lab look at glucose history
• Most labs would do a GTT after discussion with the clinician even if the blood glucose was below the range at which a GTT would usually be recommended.

• 6 labs commented that a random glucose >11.1 (or 11.0) was consistent with DM. 4 of these suggested repeating to confirm one lab suggested repeating or considering a GTT.
• 2 labs commented that glucose >7.8 and <11.1 suggested IGT.
• 2 labs suggested fasting glucoses when random >5.5 (1 lab) or 6.0 (1 lab)

• 4 labs commented on impaired fasting glycaemia in glucose range 6.1 – 6.9 mmol/l
• 6 labs commented that the glucose was indicative of DM (at >6.9 mmol/l, [4 labs] >7.0 mmol/l)[2 labs] 5 of these labs suggest repeating to confirm and one also suggested considering a GTT.
• 1 lab commented that a glucose <5.6 mmol/l excluded DM
• 1 lab recommended repeat if glucose > 7.0 – 8.0 plus HbA1C

• 12 labs sited WHO/ADA/BDA at various dates.
• 1 lab Diabetes Care 2003; 26 3160-3167.
• 1 lab “A group of clinicians got together and agreed these cut off values years ago”.

• The critical limits ranged from <2.0 at the lower end to >35.0 at the upper end.
• Several laboratories had different phoning ranges for GP/OPD/inpatient requests as well as different ranges for diabetics and non diabetics, fasting or non fasting samples.