Adulterated specimen: A specimen
that contains a substance that is not expected to be
present in human urine, or contains a substance expected
to be present but is at a concentration so high that
it is not consistent with human urine.
A substance that when introduced into the body stimulates
the production of an antibody. Antigens include toxins,
bacteria, foreign blood cells, and the cells of transplanted
Creatine: A white
crystalline nitrogenous substance C4H9N3O2 found especially
in the muscles of vertebrates either free or as phosphocreatine
Level (Threshold): The defined concentration
of a substance in a specimen at or above which the test
is called positive and below which it is called negative.
This concentration is usually significantly greater
than the sensitivity of the assay.
specimen. A specimen with creatine and specific
gravity values that are lower than expected for human
Chromatography: A process in which the specimen
is vaporized and injected into a stream of carrier gas
(as nitrogen or helium) moving through a column containing
a stationary phase composed of a liquid or particulate
solid and is separated into its component compounds.
Immunoassay: A laboratory
technique that makes use of the binding between an antigen
and its antibody in order to identify and quantify the
specific antigen or antibody in a sample.
drug test: The result of a drug test for a
urine specimen that contains an unidentified adulterant
or an unidentified interfering substance, has abnormal
physical characteristics, or has an endogenous substance
at an abnormal concentration that prevents the laboratory
from completing or obtaining a valid drug test result.
There can be several reasons for an invalid or unsuitable
- Not suitable for testing
- pH is out of range
- Temperature of the specimen
is out of range
- GC/MS interference
- Immunoassay interference
- Interfering substance
- Creatinine < or = 5 but
the specific gravity is within normal limits
Spectrometry: An instrumental method used in
conjunction with Gas Chromatography that provides accurate
information about the molecular mass and structure of
complex molecules. This technique can identify and quantify
extremely small amounts of drugs or metabolites by their
Review Officer: A medical professional, most
often a licensed physician, who is responsible for receiving
and reviewing all confirmed “positive ”
drug-test results from the laboratory. The MRO is generally
responsible for contacting all individuals testing “positive
” to inquire about possible prescription or over-the-counter
medications which may have caused a “positive
” test result. The MRO must have knowledge of
substance-abuse disorders and the appropriate medical
training in order to interpret and evaluate “positive
” test results, together with an individual’s
history and any other relevant medical information.
A compound produced from the chemical changes
of a drug in the body.