you'll pass if you do the following:

1)exersize daily (work up a sweat), up until 2-3 days before the test.

2)go to GNC and buy a 7 day cleanser or milk thistle, psyllium husk seeds and garlic pills. these will help your liver and digestive system, so it'll push out all the bad thc particles out of your system faster. Not to mention these herbs are really good for you regardless.

3)eat healthy. Eat as much fiber as you can and poop as much as you can everyday.

4)drink water. Not a lot though because it won't flush your system but will keep you hydrated and healthy

5)piss as much as you can daily.

6)ABSTAIN FROM THC (OBVIOUSLY!)

from now up until your test, practice the dilution sticky. i think 28 days is PLENTY of time to clean yourself out as long as you abstain up until the day of your test. I took a test and smoked two days prior and passed mine. I'm by no means a heavy smoker but still!

Even if you're overweight and have a slow matabolism you should still be able to pass your test if you follow the 6 steps above.