Nandrolone use is indirectly detectable in urine tests by testing for the presence of 19-norandrosterone, a metabolite of this molecule. The International Olympic Committee has set a limit of 2 ng per ml of urine as the upper limit, beyond which an athlete is suspected of doping.
"Urine analysis as a method of detecting nandrolone abuse has recently become somewhat controversial, following studies by the University of Aberdeen showing that the metabolite product can also show up in urine in quantities above the upper limit from a combination of high-protein diets utilising the legal nutritional supplement creatine and hard cardiovascular exercise. The reason for this unexpected result has not been determined. Another possible (though unlikely) reason for a false positive result is the consumption of beef from cattle treated with steroids including nandrolone (used in overturning the verdict against the bobsleigh racer, Lenny Paul). Heavy consumption of the essential amino acid lysine (as indicated in the treatment of cold sores) has also shown false positives in some and was cited by American Shotputter C.J. Hunter as the reason for his positive test. A final possible cause of incorrect urine test results is the presence of metabolites from other anabolic steroids. As a result of the numerous overturned verdicts, the testing procedure was reviewed by UK Sport [1] in 2000".
i guess if u ever get caught blame it on creatine and beef from cattle