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Family Physician
Family Physician, Doctor (MD)
Category: Health
Satisfied Customers: 12816
Experience:  Emergency Medicine and Family Practice for over 26 years
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If you test poss on a sweat patch for meth 49.0 ng/mL how

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If you test poss on a sweat patch for meth 49.0 ng/mL how much is 49.0? and what would it take to make someone test poss by 49.0 ng/ml
Unfortunately, there is no way to calculate or determine the specific amount of drug used (dose) or the frequency of use. Small doses used frequently can give similar levels as higher doses used less frequently. There is also variation between different individuals in the metabolism of the drugs.
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Customer: replied 4 years ago.

So what your telling me is with the sweat patch it only can tell the presence of a drug? It can't tell ya when or how much of the drug was taken. The body comes in contact with all kinds of stuff. could a person that has never used any drugs come back Poss on the sweat patch. And would a person be more likely to test poss if he works in the heat all day and sweats buckets, then someone working in the a/c and not even break a sweat?

There are reports of false positives with the patch sweat testing devices. There are a number of possible causes including external contamination of the device after it has been placed on the skin OR contamination of the skin before the device was placed on the skin.

The exact effect of exercise, heat exposure and rate of perspiration on the ability to detect drugs with patches has not been well established.
Customer: replied 4 years ago.

I know this question is strictly a matter of opinion. I would just like the opinion of a professional such as yourself. From a doctors point of view, if a person has had the sweat patch on 3 times. two of which were neg, then the third comes back 49.0 ng/mL poss. Would that be enough for you as a doctor to remove a 4 yr old, 7 yr old, and 8 yr old, that have never tested poss for anything, from their home and parent and place in foster care? After the patch results were back this person also went to their doctor and had a urine and hair stat taken which were both neg.

There are advantages and disadvantages of the various types of testing. Hair tests are relatively insensitive to intermittent use of any drug. A negative hair test does not prove that the individual did not use small amounts during the time that the patch was in place.

A negative urine test also does not really prove that the person was not using since the cocaine metabolites are only found in urine for 48-72 hours. By the time the person went for the urine test after getting the results of the patch test, all the cocaine would be out of the body.

Obviously, this is more of a legal issue than a medical issue. There are reports of false positives with the patch, so an attorney could question the validity of the results from a legal perspective. The courts tend to error on the side of the safest approach for the child.