1.	Independent of perceptable simultaneous symptoms hypoglycemia is defined as a blood glucose measurement in capillary blood below 40 mg/dl (2.22 mmol/l).
2.	Blood glucose readings between 40 and 50 mg/dl (2.22-2.78 mmol/l) represent hypoglycemia, if adrenergic and/or neurological symptoms are simultaneously observed.

Comment: for patients without Diabetes mellitus

1.	The blood glucose measurement has to be performed by means of valid enzymatical - photometrical or electrochemical - methods. Glucose-Analyzers used in laboratories are suited. (Example:HemoCue®-Glucoseanalyzer )
2.	"Glucose-Meters" based upon dry chemistry strips have been developed for diabetic patients. They are unreliable in the hypoglycemic range ( <50 mg/dl) and only useful for rough estimations to be checked by laboratory chemistry.
3.	Blood glucose levels above (>) 60 mg/dl ( >3.33 mmol/l) have to be considered as normal levels, even when symptoms or complaints compatible with hypoglycemia are simultaneously observed. Such levels definitely rule out the diagnosis of hypoglycemia as a cause of the symptoms.
4.	Low-normal blood glucose levels between 50 and 60 mg/dl (2.77-3.33 mmol/l) represent a range of uncertainty, which may occasionally be reached in completely healthy persons as well as regularly during fasting periods for more than 24 hrs. If blood glucose in this range levels do occur in the overnight fasted patient, before main meals or 3 - 5 hrs. after main meals, a physician considered to be familiar with hypoglycemia should be consulted.