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Fasting Blood Glucose Levels in Diabetes

Updated at: Aug 29, 2013
Written by: Gunjan RastogiPublished at: Jun 08, 2012
Fasting Blood Glucose Levels in Diabetes

Fasting blood glucose levels in diabetes is measured using oral glucose tolerance test. It requires a person to fast for at least ten hours before the test.

Fasting Blood Glucose Levels in DiabetesThe “oral glucose tolerance test” is carried out to check one’s fasting blood glucose levels. The individual being checked is asked to not eat or drink anything except water at least for ten hours before the test. That is why oral glucose tolerance test is called fasting glucose test. Fasting should not be continued for more than 16 hours. Initially, blood is drawn and the person is asked to drink a “glucola” which contains good amount of sugar in it. After this, blood is analysed for five times in a period of three hours.


In a non-diabetic, the blood glucose levels shoots up after consumption of glucose drink, but within few hours falls back to normal levels. In a diabetic, levels of blood sugar show an alarming increase after having glucola and take much more time to drop back to normal levels. This is because  in a diabetic, body cells develop insulin resistance or body does not produce insulin at all.


Measurements of blood glucose during the oral glucose tolerance test can fluctuate to some extent. Thus, your physician may be required to do the test again. The tolerance test can lead to one of the given conclusions:


Impaired Glucose Tolerance

If the fasting blood glucose measurements of an individual is same or  greater than 110 and less than 126 mg/dL, he is said to have impaired glucose fasting. This indicates that the individual has chances to develop diabetes in future.  

An individual is said to have impaired glucose tolerance if the two hour end result of the oral glucose tolerance test is equal to or exceeds 140 but is lower than 200 mg/dL. This is another risk factor for diabetes risk in the future.



An individual is termed diabetic when his two hours result of oral glucose tolerance tests are more than or equal to 200 mg/dL. In order to confirm that the person is diabetic, same test is conducted on the next day. Currently doctors are considering to lower the higher value to 180 mg/dL. This will help to diagnose more individuals with mild diabetes and aids can be taken early to avoid diabetes complications.


Gestational Diabetes

If an expecting woman has a fasting glucose level higher than 105 mg/dL, a 1-hour glucose level higher than 190 mg/dL, a 2-hour glucose level higher than 165 mg/dL, or a 3-hour level higher than 145 mg/dL, she is diagnosed with gestational diabetes.


Read more articles on Diabetes.




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