Hello, False-positive results for amphetamine and methamphetamine were the most commonly reported. The most commonly used tests to screen urine for drugs of abuse are immunoassays, even though false-positive results for drugs of abuse have been reported with a number of these rapid-screening products. Results from such tests should be confirmed using additional analytical methods, including gas chromatography–mass spectrometry. Following drugs can results in false positive test for Methamphetamine: ephedrine, pseudoephedrine, desoxyephedrine, propylephedrine and phenylephrine. Dexedrine (Dextroamphetamine), Ritalin (Methylphenidate) and Adderall (made of four different amphetamine compounds) ills containing phenylpropanolamine such as Accutrim or Dexatrim Even kidney infection, kidney disease, liver disease and diabetes could all cause a false-positive for methamphetamine. Thus it is possible to have a false positive for your tests. Please confirm with some analytical methods like Gas- Chromatography. Hope this helps. please write back for further queries. Wishing you good health.