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What causes a false negative for Morphine in a urine test?

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Posted on Tue, 19 Jul 2016
Question: if a urine test was givin on 3-31-16 at 3:30pm and not received by the testing lab till 4-6-16 could that cause the false-negative I got for morphine sulfate and or alprazolam? the morphine should both positive and negative? I take 2 60mg 2x a day and .5mg of alprazolam 3x a day. been on this regiment for 9 yrs.
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Answered by Dr. Ilir Sharka (5 hours later)
Brief Answer:
I would recommend as follows:

Detailed Answer:
Hello!

Welcome and thank you for asking on HCM!

I carefully passed through your question and would explain that this may lead to a false negative test.

You should know that two common potential causes for false-negative opiate tests are using the wrong test for a specific opiate and having an insufficient concentration of an opiate in the sample.

There are two main tests for this purpose: EIA testing and GC-MS testing.

The second is more specific and is used to differentiate the false positive or false negative tests resulting from EIA testing.

I recommend repeating the urine test again, with urine brought to the lab within 4 hours after urinating and perform both above mentioned tests.

Kind regards,

Dr. Iliri
Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar
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Answered by
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Dr. Ilir Sharka

Cardiologist

Practicing since :2001

Answered : 8280 Questions

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What causes a false negative for Morphine in a urine test?

Brief Answer: I would recommend as follows: Detailed Answer: Hello! Welcome and thank you for asking on HCM! I carefully passed through your question and would explain that this may lead to a false negative test. You should know that two common potential causes for false-negative opiate tests are using the wrong test for a specific opiate and having an insufficient concentration of an opiate in the sample. There are two main tests for this purpose: EIA testing and GC-MS testing. The second is more specific and is used to differentiate the false positive or false negative tests resulting from EIA testing. I recommend repeating the urine test again, with urine brought to the lab within 4 hours after urinating and perform both above mentioned tests. Kind regards, Dr. Iliri