Reread my post above:

48 hours before the real test, load up on the red meat and creatine supplements. The day of the test, have some salty foods, ramen noodles, mcdonald's fries, whatever, to make sure your SG and creatine look good.

if you want to, you can get strips that test SG and creatine, so that you know that if you are passing with 20 oz of gatorade, your SG and creatine are good too. you have plenty of time to order more test strips from ebay and some adulterant strips. How to Pass a Drug Test? Here's a Quick Way to Pass Drug Tests - Drug Testing