The way to diagnose diabetes is sometimes a yucky one
Most GP's will at one stage check their patients blood glucose levels, either to rule out diabetes due to a clinical suspicion, or as part of a general check up, for instance for a life insurance.
If, after a fasting (for eight hours prior to the test nil to eat or drink) blood glucose test the result is ambivalent (i.e. between 6.1 - 6.9 mmol/L glucose concentration in venous blood) the patient will be send for the dreaded oral glucose tolerance test.
This is how it works: the patient appears fasted at the lab and a first sample will be taken. Then the patient needs to drink the most sickenly sweet stuff ever: 75 g glucose concentrated in a glass: that's worse than Vanilla Coke.
After two hours another bloodsample is taken: the sample is then analysed: