Diabetes can be diagnosed if a fasting plasma glucose level, after 8 hours, is > 7.1mmol/L or a random plasma glucose level is >11.1mmol/L. It can also be diagnosed after a oral glucose tolerance test where the person being tested fasts for at least eight hours, is then given a 75 g glucose load (in the form of a very sweet drink), and the blood sugars are measured at one or two hour intervals. Diabetes is diagnosed if after two hours the plasma glucose level is > 11.1mmol/L. Patients with plasma glucose >7.8 mmol/L but <11.1 mmol/L, two hours after a 75 g oral glucose tolerance test are considered to have impaired glucose tolerance. In pregnancy, there is an increased glomerular filtration rate in the kidneys, and as a result in many pregnant women there is leakage of glucose into the urine. This does not diagnose diabetes, but would prompt the use of either a fasting plasma glucose test or an OGTT to confirm a diagnosis of gestational diabetes.
These Q&A’s are for educational purposes and should not be relied upon as a substitute for medical advice you may receive from your physician. If you have a medical emergency, please call 911. These answers do not constitute or initiate a patient/doctor relationship.