Immunoassays
| Substance | False positives |
|---|---|
| Alcohol | Short-chain alcohols (e.g. isopropyl alcohol) |
| Amphetamines | Amantadine Benzphetamine Bupropion Chlorpomazine Clobenzorex l-Deprenyl Desipramine Dextroamphetamine Ephedrine Fenproporex Isometheptene Isoxsuprine Labetalol MDMA Methamphetamine Methylphenidate Phentermine Phenylephrine Phenylpropanolamine Protethazine Pseudoephedrine Ranitidine Ritodrine Selegiline Thioridazine Trazodone Trimethobenzamide Trimipramine |
| Benzodiazepines | Oxaprozin Setraline |
| Cannabinoids | Dronabinol Efavirenz Hemp-containing foods NSAIDs Proton pump inhibitors Tolmetin |
| Cocaine | Coca leaf tea Topical anesthetics containing cocaine |
| Opioids, opiates, and heroin | Dextromethorphan Diphenhydramine Heroin Opiates (codeine, hydromorphone, hydrocodone, morphine) Poppy seeds Quinine Quinolones Rifampin Verapamil and metabolites |
| Phencyclidine | Dextromethorphan Diphenhydramine Doxylamine Ibuprofen Imipramine Ketamine Meperidine Mesoridazine Thioridazine Tramadol Venlafaxine and desvenlafaxine |
| TCAs | Carbamazepine Cyclobenzaprine Cyproheptadine Diphenhydramine Hydroxyzine Quetiapine |
