Questions about False Positives in Drug Testing, page 194

False Positives Forum

This forum is intended to help those who Do NOT Abuse Drugs. We do NOT support the illegal use of any substance. If you have experience with false positives, share your experience. What would you tell someone about drug testing and false positives? Please remember that we do not give medical or legal advice.

Custody over my son
Date: 4/19/2012
I dont have 35 dollar on a credit card I’m trying to get custody over my son. I have had him 10 years


AskDocWeb: Sorry Tony, it seems that your post got cut off. Please try again.

Positive for benzodiazapine
Date: 4/19/2012
I’m a veteran and take suboxon for opiate management, part of the stipulations of my suboxon treatment is that I cannot take any benzodiazapines.. I gave my urinalysis and it was positive for benzodiazapine, the only other thing I have been taking was Zantac and fomotadine and ranitidine, could that have caused the false positive?


AskDocWeb: That is unlikely, those three meds have not been reported to cause a false positive for benzodiazapine but your test result may have another cause. If they do confirmation testing then we suggest you take advantage of that.

Lost job because of false positive
Date: 4/19/2012
I was currently discharged by my job for a false positive and I was prescirbed Ibuprofen and Naproxen and take whenever I feel pain the Naproxen is 500mg and the ibuprofen is 800mg. I am currently appealing the discharge and was hoping that I can have a doctor to contact confirming that these medications do indeed cause false positives my test came up for thc and I do not do any drugs of any kind and would appreciate the help so I may be able to go back to work and support my family.


AskDocWeb: Since you are appealing this you need to find out if the results were confirmed by additional testing or not. Others have won because of a lack of confirmation testing. If you go the page that lists causes of false positives and look up each of your meds, you will see a reference numbers for each substance. Clicking on the reference number takes you to the page where you can find links to the documentation. There are some pretty solid references there: Legal Bulletin from the Lewisburg Prison, PA. The Lectric Law Library, Toxicology Lab Technical Brief from Dr. Joseph Graas, Ph.D., Lawyers And Settlements etc.

Date: 4/20/2012
I recently have been taking Allegra ND and was wondering if it causes any false positives for a urine drug test.


AskDocWeb: Allegra D contains pseudoephedrine so it may cause a false positive for amphetamines. This is why you should show your prescriptions and whatever OTC meds you are taking and that typically keeps you out of trouble.

False negative pregnancy test?
Date: 4/22/2012
Can indocin or methrotraxate cause a false negative pregnancy test?


AskDocWeb: Neither of those medications are known to cause a false negative result on pregnancy tests. False negatives are relatively rare but can occur if a pregnancy test is done too soon after becoming pregnant, the test sensitivity is too low, or the urine too diluted. Here is a little more detail on each of these reasons.

Once an egg becomes fertilized, it takes between 7 to 10 days for the fertilized egg to travel to the uterus and implant itself into the wall of the uterus. It is not until the fertilized egg is implanted in the wall of the uterus that the woman’s body begins to make hCG (Human chorionic gonadotropin), which is the hormone that indicates pregnancy. The amount of this hormone present in the urine of pregnant women typically doubles each day following implantation but the rate of increase varies greatly from one woman to the next and from one pregnancy to the next. Testing too early means the level of hCG has not yet reached a concentration level that the test can detect. Only the most sensitive of the pregnancy tests can detect the increased hCG hormone within 1 to 2 days of implantation. However, by the time that a woman has actually missed her period, almost all pregnancy tests should be able to provide a positive result.

Test sensitivity is too low: Home tests kits test between 20 and 100 miu’s of the hCG hormone per milliliter. The more sensitive the test, the earlier pregnancy can be detected. Here is a comparison of hCG levels in weeks since the last menstrual period.

Not pregnant

less than 5 miu/ml

3 weeks pregnant

5 – 50 mIU/ml

4 weeks pregnant

5 – 426 mIU/ml

5 weeks pregnant

18 – 7,340 mIU/ml

6 weeks pregnant

1,080 – 56,500 mIU/ml

7 – 8 weeks pregnant

7, 650 – 229,000 mIU/ml

9 – 12 weeks pregnant

700 – 288,000 mIU/ml

Drinking large amounts of fluids before collecting a urine sample can dilute the amount of hCG present in the urine. If your schedule prevents you from using first in the morning urine, avoid drinking a lot of fluids before testing – and try to hold your urine for several hours before collecting a sample.

In rare situations, low hCG levels can theoretically indicate a problem with the pregnancy or an ectopic pregnancy. If you have missed your period and are experiencing pregnancy symptoms even though you have a negative test result, you may wish to contact your doctor about a blood hCG test to determine the cause of the missed period.

Positive for benzodiazepines
Date: 4/23/2012
I had 3 pee test at Dr. office in 4 months. All 3 showed negative for Percocet which I take 4 10/650 per day. But the last drug test showed negative for percocet and postive for Benzodiazodiazepines. I asked could zanax or Benadryl or Energy shots cause that show postive she said no. They gave me zanex script for 1 for a MRI test.

Long time ago another dr said my metabolism causes my test come up negative but this dr said no and plus I’m taking B 12 shots at dr office does that boost metabolism? and b 12 under tongue pill every day. I could care less if they ever give my meds back I can go another Dr. But I want to prove to them I’m telling truth. I was so embarrassed and humilated knowing all employees was acting funny toward me prior to them telling me.

I’ve been going to this Dr office for years there’s 4 dr there never know which one going to see you. I thought so much of this dr office and they had month to tell me but 2 wait till 4pm on a Friday knowing it was impossible to go to another dr before Monday after taking these for years and I was sick on top of this I am mad, hurt, and furious.

I haven’t been able to take care of my family this weekend due to severe pain and withdrawels I’ve been taking phenergan, energy shots, excedrian with caffenine. Only been out of bed few min all weekend. I was honest took my meds and if I ever took anything different I always told which ever dr I seen.


AskDocWeb: You could print out the page at but that wouldn’t prove that your particular test result was a false positive for benzodiazepine. For that you would have to get a confirmation test done on the original sample. Whether or not they would be willing to do that is doubtful, especially if you are no longer a patient at that clinic.

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