Is it possible that I can use the excuse that I've been bulking up on creatine? I'm a big muscular guy. And they wouldn't know what I looked like a year ago. And given my bulk, excessive creatine could be an explanation on how I that big.
I dont understand what youre trying to get at here. Creatinine levels (elevated or diminished) have no bearing upon whether you test postive for THC or not. Creatinine is checked (along with S/G) to determine an overly-diluted urine sample.

And to clarify my question, I was more looking for an answer that the testing center will have a more elaborate testing kit for my urine. Lets say I'm clean with the test kit I have with my test run, even with my usage, as you said, dilution might not work. And I follow the same process the day of the testing. Because of their better testing methods, would it still come up dirty?
That question has been answered already in post #6. As stated, it applies to both - the home kits and the kits used at the lab.

Basically, if I put a cup of warm water in the testing strip, would it come back negative or N/A?
It would register a negative on a test kit that checks for drug metabolites.

But when a validity test is run, it will not fly. Straight tap water will cause the creatinine and S/G to be diminished to the point to where the sample will be ruled "not consistent with human urine" .