I read that if your niacin or creatinine levels are high the military will send the test to an even harder tester that detects at 15ng )
Thats BS all the way.

For starters niacin does nothing to pass a U/A. Niacin levels are not even checked in a U/A.

High creatinine levels are a non-issue. There are no upper limits established for creatinine. Low creatinine levels are what the labs check for. Low creatinine levels indicate overdilution.

Finally, An initial assay screen is done on all urine samples, even on the ones that fail the dilution checks.