I recently have failed a drug test for methamphetamines. What could have made a false positive?

Anywhere, here's a (long!) list of medications that are likely to result in a false positive for methamphetamine:

<< Over-the-counter cold and allergy remedies that contain ephedrine, pseudoephedrine, propylephedrine, phenylephrine or desoxyephedrine: Nyquil, Contactd, Sudafed, Allerest 12-Hour, A.R.M., Triaminic 12, Ornade, Tavist-D, Dimetapp, Sinex, Neosynephrine, Actifed, Bayer Selectd Maximum Strength Sinus Pain Relief Caplets, Contact Non-Drowsy Formula Sinus Caplets, Dristan Cold Caplets, Maximum Strength Sine-Aid Tablets, Maximum Strengeth Sudafed Sinus Caplets, Maximum Strength Tylenol Sinus Gelcaps, No Drowsiness Sinarest Tabs, Sinus Excedrin Extra Sterength Caplets, Characol Sinus, Drixoral Cold and Flu, Efidac/24, Phenergan-D, Robitussin Cold and Flu. Over-the-counter diet aids containing phenylpropanolamine: Dexatrim, Accutrim. Over-the-counter nasal sprays: Vicks inhaler, Afrin. Asthma medication: Marax, Bronkaid tablets, Primatine Tablets. Prescription medication: Amfeprainone, Cathne, Etafediabe, Morazone, phendimetrazine, phenmetrazine, benzphetamine, fenfluramine, dexfenfluramine, dexdenflurarnine, Redux, mephentermine, Mesocarb, methoxyphenamine, phentermine, amineptine, Pholedrine, hydroymethamphetamine, Dexedrine, amifepramone, clobenzorex, fenproyorex, mefenorex, fenelylline, Didrex, dextroamphetamine, methphenidate, Ritalin, pemoline, Cylert, selegiline, Deprenyl, Eldepryl, Famprofazone >>

Hopefully, if you give this information to them, they'll allow you to schedule another test - and be sure that beforehand, you AVOID any medication that may cause the false results, especially the Robitussin. I pray all goes well for you and your son. Bravo for cooperating with CPS and doing everything you could to bring him home - that's wonderful.