I need to take in a urine sample for ds to be tested, but he does'nt have his first wee til about 10.00am, he is almost 5, I have tried getting him up earlier and getting him to drink, but it does'nt work. The sample has to be taken to the gps on a morning. Can I do it the night before or will it be too old, otherwise he will have to have a morning off school, while I wait patiently for him to wee