Blood testing has a short window of detection, usually 72 hours max. If you pass the home test with your first void of the day, your dirtiest, you have a great chance of passing the real thing. The home tests are about 95% accurate. Drinking water for days and days before the test will not help you. Same thing goes for the cranberry juice. It has some value on the day of the test but not days before. Start with the home test before wasting your money on Strip. You have time to buy home tests online for cheaper than a drug store too.