They will be trying to ascertain if your Dad is diabetic or not. The test is to see how he reacts to the drink they will give him.
Basically they sit you a chair in a boring room :roll: and take some blood. They then give you a sickly sweet drink, to drink as fast as possible.
Then you are left to read a magazine, watch TV (if there is one) and come back 2 hours later and take another blood sample.
This last blood sample will determine how well you are coping with the sugars in the drink.
The worse part of the test, is drinking the sugary drink :lol:
I would advise that your Dad takes a book or magazine/crossword puzzle with him, to keep him from getting bored :roll:
Not too sure if you can have Lucozade instead of the glucose drink. Maybe take a bottle along with you, it must certainly taste better than the glucose drink :lol: