I am wondering how (if possible) the concentrations of certain drugs in a urine specimen can be used to indicate innocent/unknowing ingestion of a drug. I have an individual that tested positive for codeine (for which they do not have a prescription). The individual alleges that he received a tablet containing codeine without his knowledge. The results of his urinalysis generated 19,000 ng/mL of codeine. Given these results, would it be scientifically possible to justify unknowing/innocent ingestion.