From the wiki page on GTT
http://en.wikipedia.org/wiki/Glucose_to ... TT_results
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Interpretation of OGTT results
Fasting plasma glucose (measured before the OGTT begins) should be below 6.1 mmol/L (110 mg/dL). Fasting levels between 6.1 and 7.0 mmol/L (110 and 125 mg/dL) are borderline ("impaired fasting glycaemia"), and fasting levels repeatedly at or above 7.0 mmol/L (126 mg/dL) are diagnostic of diabetes.
A 2 hour OGTT glucose level below 7.8 mmol/L (140 mg/dL) is normal, whereas higher glucose levels indicate hyperglycemia. Blood plasma glucose between 7.8 mmol/L (140 mg/dL) and 11.1 mmol/L (200 mg/dL) indicate "impaired glucose tolerance", and levels above 11.1 mmol/L (200 mg/dL) at 2 hours confirms a diagnosis of diabetes.
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If, as I suspect, the 16 refers to mmol/L, then it puts you in the diabetic range, which starts at 11.1 mmol/L
They should really do it twice though and it depends on what the initial fasting glucose result was.
The 16 on its own won't hurt you. You would have hit 16 at some point in those 2 hours even if you had not been diabetic. Everyone spikes. The diabetic however takes much longer to come down. Normally healthy people are expected to 'return to normal' within two hours'. You might be back down after 3 hours which is better than someone who is still very high after 4 or 5 hours. It's the shape of the curve that is important, not the height.