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Chris C.
Chris C., Nurse
Category: Health
Satisfied Customers: 1078
Experience:  Nurse with with 10+ yrs. in wellness care, geriatrics, hospice and acute care.
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why does tylenol pm show up as tca positive in a drug screen?

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why does tylenol pm show up as tca positive in a drug screen? Or the drug test was bad. I don't take any antidepressants for this to show positive or any controlled drugs, diet pills for that matter.

Chris C. :

There are hundreds of drugs and other substances including supplements that cause a false positive. If you get a false positive it should not be of concern. The reason is that all positive results must be verified via GC/MS (gas chromatography/ mass spectrometry) test.This will rule out all false positive results and give a 100% accurate result. The initial screenings are not very accurate and it is very common to have a false result such as you have had.

Chris C. :

The reason for the positive result is diphenhydramine which can potentially cause a false positive with laboratories that screen by enzyme immunoassay. Diphenhydramine is found in some sleep aids. Examples are Tylenol PM, Excedrin PM, Unisom and many others.

Chris C. :

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Chris C. :

There are hundreds of drugs and other substances including supplements that cause a false positive. If you get a false positive it should not be of concern. The reason is that all positive results must be verified via GC/MS (gas chromatography/ mass spectrometry) test.This will rule out all false positive results and give a 100% accurate result. The initial screenings are not very accurate and it is very common to have a false result such as you have had.

Chris C. :

The reason for the positive result is diphenhydramine which can potentially cause a false positive with laboratories that screen by enzyme immunoassay. Diphenhydramine is found in some sleep aids. Examples are Tylenol PM, Excedrin PM, Unisom and many others.

Chris C. :

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Also, this will give you some great information on drug testing and false positives: http://dig.pharm.uic.edu/faq/2011/Feb/faq1.aspx