We had a piggy diagonosed as diabetic. The diagnosis was made as she had developed cataracts in both eyes and had a high glucose content in her urine.
I would recommend you contact the CCT. Unfortunately the piggy had other complications and is sadly no longer with us.
Below is a copy of an email from the CCT which may be useful.
" ....
Whilst I am not saying that your Guinea Pig doesn't have Diabetes, they can sometimes be thought to have the condition even if they haven't. This is often due to (as you have said below) a high glucose content in the urine, however, whilst I note your other guinea pig has the same diet and has a normal level of glucose it is still possible that he dry mix food is causing this abnormally high reading.
Can you tell me what food mix you use? Some of the food mixes contain EC Permitted Colourants. Whilst not conclusive, Vedra's studies do indicate a high incidence of abnormal glucose readings in the urine of guinea pigs whose diets have included food mixes with these colourants. These colourants can also be linked to urinary tract infections.
Before placing a guinea pig on an Insulin Lente medication regime, we would undertake a test along the following lines (something you could, if you choose do for yourself):
1) Place the guinea pig on a test diet for three weeks using ONLY the following ingredients:
* Rolled or crushed oats
* Hay
* Cabbage
If the high glucose reading was due to the chemicals, at the end of the three weeks test, the glucose will be either considerably reduced or gone altogether.
...."