I am just trying to avoid supplementing with B complex and creatine on the day of the test due to the high level of scrutiny the sample will be under.

Sounds like a bunch of scare tactics. And theyre working on you.

For starters, creatine is found in all human muscle tissue. The body metabolizes creatine into creatinine. Creatinine, being the waste product, is what the labs test for, not creatine.
Creatinine is expected in a urine sample. Labs check the creatinine level to determine a diluted sample. Urine samples with a creatinine level over 20 mg/dL are satisfactory. Samples between 2 -20 mg/dL are ruled "too-dilute".
There are no upper limits established for creatinine, therefore samples cannot be flagged for high creatinine levels.
Still, care must be taken when loading up on creatine supps. Overloading on creatine will have you sitting on the toilet seat for long periods of time.