A friend submits a hair folicle test...She was tested for Amphetamines
and Methamphetamines..The results were negative for Amphetamines,
positive for Methamphetamines..Can amphetamines use give a positive
for Methamphetamines and not for Amphetamines...

The proteins that attach to each of these are significantly different
and they do not influenece each other.So amphetamines use cannot in
any way give a positive
for Methamphetamines and not for Amphetamines.

Thanks

source: FDA Hair follicle tests

In a hair follicle test, the hair is usually first evaluated using
tests that are not terribly specific or quantifiable.  Once anything
tests positive, the lab confirms the initial results using gas
chromatography and mass spectroscopy (GC/MS), which can identify
specific molecules, are very accurate and can be quantified to provide
a threshold for a positive result.

===========================================================================

The body turns methamphetamine into amphetamine as it is metabolized,
so one might wrongly conclude that testing cannot differentiate the
use of these substances.

Q: What is the difference between Methamphetamine and Amphetamine?
A: Both amphetamine and methamphetamine are potent symphathominetic
agents. Methamphetamine is the parent drug. It metabolizes (or
changes) into amphetamine in the body. Methamphetamine and/or
amphetamine are excreted in the urine. A positive result for
Amphetamine can also be interpreted as a positive test for
methamphetamine.

[ http://bp.kmdc.ru/drug_testing_faq.htm ]

===========================================================================

In practice however, when the concentration of the methamphetamine is
significantly higher than the amphetamine concentration, it appears
that the amphetamine is present as a metabolite of methamphetamine.

[ http://workplace.samhsa.gov/DrugTesting/MedicalReviewOfficers/MROCaseStudies022005.pdf
]

===========================================================================

To assist with differentiating legitimate amphetamine use with the use
of illicit amphetamines or methamphetamines, a d&l isomer test is used
to determine the relative concentrations of particular metabolites.

[ http://www.labcorp.com/ots/tox_faq.html ]