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Codeine v. Hydrocodone - False positive on drug test?
SWIM is prescribed fentanyl patches and tylenol with codeine by her pain management doctor.
At her last drug test (a spit test), she came up with a positive for hydrocodone. She has never used hydrocodone and has no idea how this could have happened. She hasn't used any drugs other than what she is prescribed and has never failed a drug test before this.
SWIM's doctor swears that it wasn't caused by the codeine in the Tylenol-3, but she's not sure she believes him.
Can anyone suggest how this might have happened? One more dirty test and SWIM is out a pain management doctor which, due to chronic health issues, she really cannot afford to have happen.
Re: Codeine v. Hydrocodone - False positive on drug test?
sFirst of all a spit test will not test for specific opiates, it will come back positive for opiates and does not have the capability of distinguishing exactly what opiate it was.
Yes, I myself in 1989-1993 tested UA's at the Colorado Department of Health. I worked in the Toxicology section, in which we processed 650-800 UA's a day. We tested probationers, parolees, police officers, doctors, nurses, drug counselors, and a few other professions.
The first question you ask them is this:"What modality (or technology did you use to test my UA, Elisa, Emit, Saliva test or what?) Because those tests will only distinguish if it's an opiate, barbiturate, methamphetamine, cocaine, THC, PCP, benzodiazepine and other drugs, but it will not tell the tester you took Valium, Xanax, codeine, hydrocodone, Seconal or amobarbital. They just can't do it, the GC/MS can.
The second question is: Did you confirm the UA test with a GC/MS (gas chromatograph/mass spectrometer) to confirm the results (we used three modalities (FIA) also.
If the UA came up hot on all three screens, it would be called hot and sent back to the proper authorities. If it came up hot on the EMIT or ELISA and not the other two or one, then it would be sent back negative.
You see, the first step is just to weed out all the negatives, then we might be left with 20-30 positives. Then through our FIA, some more would get weeded out, then we'd be left with 20 dirties at the time.
However, the GC/MS is the Gold Standard in UA testing, without that test being done, codeine specifically metabolizes to morphine and left over codeine in the gluconerate form. So if you were hot for codeine, we would have a sample of pure codeine to test against your sample, if the spike didn't match exactly it would be called negative. Codeine metabolizes to morphine and some codeine is left excreted unmetabolized, so we would get out pure reference, codeine and test it against yours. If the two major spikes are morphine and codeine (and we are only concerned with the codeine spike) and they didn't match, it would be called negative.
You may have to pay for the test to be done, but in a lab many things can go wrong, like over carry from someone elses urine and contamination from the pipette, if not changed every time.
Have them do a GC/MS and say you will pay for it if it comes back positive, and they will pay if it comes back negative. Sounds far, right? Right. They screwed up, and the GC/MS will make certain it is codeine and not hydrocodone. Plus, usually with these tests, they use ELISA which just comes up positive for opiates, how they can tell it was hydrocodone and not codeine is beyond me. Make sure they do a GC/MS it's worth it. The must keep all positive UA's in the freezer for at least one year. At least we did.
Good luck, the GC/MS will clear this all up.
Last edited by salgoud; 23-09-2011 at 19:41.