Frequently Asked Questions (FAQs) To the Toxicology Laboratory (2024)

Although these questions are not all related to pain drugs, they are often asked by pain management (PM) clinicians so they are worth addressing.


Will Nyquil cause a positive DOA screen?
Nyquil contains acetaminophen, dextromethorphan, doxylamine succinate and ethanol. With high consumption, the alcohol content could cause a positive alcohol screen but it should not cause immunoassays for DOA to be falsely positive at normal doses (Note: always refer to your assay's cross-reactivity specs).

My patient is taking Adderall for ADHD/ADD. Why are they positive for amphetamine? The drug Adderall contains both isomers of amphetamine. It is therefore not surprising that when amphetamine is prescribed, the urine will test positive for amphetamine.

My patient is taking methyphenidate (Ritalin) for ADHD/ADD why is the test not positive for amphetamines? Methylphenidate is not structurally similar to amphetamine. Although both drugs are used in ADHD/ADD, it should not be assumed that both will cause positive amphetamine results. Methylphenidate will not be detected with routine drug screens.

Do poppy seeds really cause positive opiate screens? Yes this is possible, as discussed earlier in the course.

Does dose correlate with urine concentration? No. Since urine concentration varies dramatically depending on how much a person drinks we cannot treat a quantitative urine drug result like we would a serum result. Although we have minimum cutoffs for drug detection in urine, there are no therapeutic ranges or 'target' ranges. Urine concentration does not parallel serum concentration in a predictable or reliable way.

Does the drug zolpidem (Ambien) cause a positive benzodiazepine screen? No. Zolpidem is not a benzodiazepine; it belongs to a different class of drugs. Although zolpidem is a sleeping aid (a hypnotic) it will not cause a false benzo or barbiturate screen.

My patient says he/she tested positive for THC due to second-hand smoke. Is this possible? No. The amount of time and exposure it would take to have the urine positive would essentially deem such exposure first-hand and not second-hand exposure.

Will tramadol, fentanyl, buprenorphine or carisoprodol be detected by the opiate/Oxy screen? No. None of these drugs will typically cause a positive result. Specific testing for these agents is needed if the clinician wants to monitor their use.

Frequently Asked Questions (FAQs) To the Toxicology Laboratory (2024)
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