blood testing? good luck with that one. Insurance companies aren't your typical drug screening; they want to know exactly what kind of person they are insuring and charge them appropriatley, so this is going to be harder than your typical pre employment/random testing ordeal.

Having said that, it probably won't matter if you have low creatine/specific gravity levels from dillution because they aren't trying to bust you so don't bother wasting money on a drink.

But you can't dillute your blood very effectively, so if they are testing that for drugs too then your best bet is to exercise heavly until a few days before test, and drink water for the urine. Maybe asprin will help, worth a try.