Test results can be attributed to human error and sample contamination. In addition, there are a number of controlled and uncontrolled substances that will cause a false positive result; these are some of the reasons why labs will immediately split your specimen into two samples. Below are some of the many substances to avoid prior to testing.
Take this very seriously, your employer or probation officer certainly will. False positives run high with the EMIT, and in some cases this is all it takes to send you to the unemployment office or a parole/probation revocation hearing. National laboratories state that the EMIT test is wrong 25% to 30% of the time, and can result in false positives from legal substances up to 38% of the time!
Antibiotics: Certain antibiotics such as Penicillin and Tetracycline can cause false positive results for heroin or cocaine.
Cold remedies, diet pills, hay fever remedies and pain relievers: In blind testing, decongestants and many diet aids resulted in false positives for amphetamine use in one third of all test samples given to 40 leading substance testing laboratories. There are more than 300 over-the-counter drugs that can cause false positives on the EMIT, and new drugs being introduced every day.
Dental/Medical treatments: Cain-based products, especially Novocaine, have been known to cause false positives for cocaine. Some legal products actually contain small amounts of illegal chemicals. All urine tests, including GC/MS will indicate a positive result because the metabolites derived from the substance are identical to the metabolites of the illegal drug.
Ibuprofen: Ibuprofen is a common pain reliever that, even in low dosages, can cause a false THC positive on the EMIT. This has supposedly been corrected.
Poppy seeds: Though an extremely concentrated amount of poppy seeds are needed to obtain a false positive for opiates on the EMIT, it is possible.