my doctors have tested me I have had several problems & have been in hospital gastro & colon test, I got MRSA staph infection from a wreck in 1989 I got it from my first surgery in 89 I had it on a rod inserted in left leg had to have it removed,I staph but not MRSA on ankle surgery done in Feb. 2013, then got MRSA on right cheek Sept 2013, went to ER each day for four days then went to another hospital for a week surgery,morphine each day when went to Er test results shwed up in these tests some different when I get info from my ins. shows Assay of benzodiazepines, alkaloids, amphetamines, cocaine, urine creatinine, dihydromorphinone, meprobamate methadone, opiates I take doxepin, alprazolam, sinus medicine constantly, vicks inhaler, what causes these tests to fail & what are they