yeah I thought about subbing but then I thought if I were working in a lab and kept seeing samples with the same exact levels for everything I would get a little suspicious...
Even if a group of samples exhibit the same levels of creatinine, this is not a concern with the labs as long as the creatinine levels dont drop below 20 mg/dL. The labs only care that urine constituents (creatinine, pH, SG, etc) are within the standards mandated by the US Dept of Health & Human Services.