Will the UA be negative when heroin-positive menses blood is mixed with clear urine?

Hello doctor,

My daughter is currently in recovery from heroin and my husband and I believe she is using it again. We check her UA's at home and mail the findings to a lab. We suspect that she is giving us her friend’s urine. However, I know that today she began her menses and the urine she gave us is blood tinged slightly. Our question is if the urine is clean for heroin and if the blood is not, will the urine drug screen come back negative?

Thank you doctor,

I would like to know if the urine drug test shows positive if there is heroin-positive menses blood mixed in a clear urine. Does heroin produce the same metabolite in urine and blood and can urinalysis detect it?

Thank you doctor,

So, does that mean you are saying when her friend’s heroin-negative urine is mixed with a drop or two of my daughter’s heroin-positive menses blood, the UA will not detect it as the RBCs do not carry heroin? Will the test come back negative? Please help as I am extremely concerned about this.

Thank you doctor,

I know it is possible to test positive for heroin on a blood tox screen. So then why would not blood from a heroin user’s menses test positive in a UA? If there is no heroin in the RBC of blood, where and why is it detectable on a blood tox screen? I read something about both blood and urine drug tests testing for the 6-MAM metabolite, which they both carry even if it is for a short time. Is this true? If it is located in the blood, I would think we would be able to prove my daughter is still using heroin. Kindly provide your opinion.

Thank you doctor,

So, then is it possible that my daughter's heroin-contaminated menses blood will yield a dirty or a positive result on the urinalysis despite the urine not having heroin in it? Also, I do believe she used heroin just an hour or two before we gave her the test.