Urinalysis Drug Testing
Enzyme Multiple
Immunoassay Test (EMIT)
The most commonly used
method of screening for drug use tests for five different substances by using
the current standard, the Enzyme Multiple Immunoassay Test. (EMIT). This test
contains the standard cutoff point of 50 ng/ml.
EMIT uses a spectrometer
to monitor the conversion process of enzymes and provides the means to measure
specific drug metabolites.
Two drug metabolites are
used, one from the donor's urine, the other from the lab. These metabolites
compete to bind with one antibody. The results from the screen are contingent
upon which of the two metabolites bond with the antibody supplied by the lab.
The result is based on which metabolite the antibody bonds with. A "Positive"
result will come from a bonding process to the lab's metabolite while a "Negative"
result will yeild no binding between the metabolites and the antibody.
Gas Chromatography
Mass Spectrometer (GC MS)
This test is administered
only used after the EMIT screen produces a positive result. A solution is added
to the urine to convert the drug metabolites into a form that is reactive to
Gas Chromatography. The sample is converted to gas at distinct intervals and
then collected to iisolate drug metabolites in the sample.
The collected sample ionized
then accelerated by an electrical field where only certain particles will pass
through. These escaping particles will then aid in determining the presence
of drug metabolites in the donor's body.
