What Affects the Test
Reasons the results may not be helpful include:
- Some drugs that may be mistaken for others. For example, some cough medicines that do not contain Reference narcotics Opens New Window may be identified as a narcotic.
- Drinking or eating some types of food (such as a food containing poppy seeds).
- Having blood in the urine.
- The amount of time between taking the drug and collecting the sample.
- Not having a large enough urine sample.
Many medicines may change the results of this test. Be sure to tell your doctor about all the nonprescription and prescription medicines you take.
|By:||Reference Healthwise Staff||Last Revised: Reference November 8, 2011|
|Medical Review:||Reference E. Gregory Thompson, MD - Internal Medicine
Reference R. Steven Tharratt, MD, MPVM, FACP, FCCP - Pulmonology, Critical Care Medicine, Medical Toxicology