The iCup, iScreen, and iCassette products employ
one-step, solid-phase immunoassay technology to
discretely detect the presence of any applicable drugs,
or their immunoreactive metabolites, in urine. The assay
uses highly specific monoclonal/polyclonal
antibodies raised against the target drugs. The test
cards contains membrane strips, on which each of the
applicable drugs conjugated to BSA is immobilized at
specific locations. The assay is based on the principle
of the highly specific immunochemical reactions between
antigens and antibodies which are used for the analysis
of specific substances in biological fluids. The drug
detection relies on the competition for binding to the
antibodies between drug conjugates and drugs which may
be in the urine sample.
In the test procedure, a sample of urine is placed in
the sample well of the device, and the sample is allowed
to migrate upward. If any of the applicable drugs is
present in the urine sample, it forms a complex with the
antibody-dye conjugate specific for that drug, and the
complex migrates toward the opposite end of the card,
passing the specific locations on the membrane where
each of the applicable drug conjugates are immobilized.
The drug in the sample competes with the drug conjugate,
which is immobilized on the membrane, for the limited
antibodies present in the form of antibody-dye
conjugate. When a sufficient amount of drug is present,
the drug will saturate the antibodies, and the
antibody-dye conjugate cannot bind to the drug conjugate
on the membrane. Therefore, a drug-positive urine sample
will not generate a line at the specific drug position
in the result window, indicating a positive result from
positive drug competition. Conversely, if a particular
drug is absent in the urine specimen, the antibody on
the antibody-dye conjugate will bind the membrane-bound
drug. In this case, a drug-negative urine sample will
generate a line at the specific drug position in the
result window, indicating a negative result from an
absence of competition with free drug.
In addition, the test card has a procedural control
built into the system, in the upper control line area.
The control line is immobilized with polyclonal
anti-mouse antibody; therefore, it will capture
monoclonal antibody-dye conjugates that pass the region,
showing a colored line in the control (validation) zone.
The line works as a procedural control, confirming that
proper sample volume was used and the reagent system
worked. If insufficient volume is used, there may not be
a control line, indicating the test is invalid.
There are a few limitations to immunoassay testing
kits. The tests are designed for use with unadulterated
urine only. There is a possibility that factors such as
technical or procedural errors may interfere with the
test and cause erroneous results. Adulterants, such as
bleach or alum, may produce erroneous results regardless
of method of analysis. If adulteration is suspected, the
test should be repeated with a new sample. A positive
test result does not provide any indication of the level
of intoxication or urinary concentration. The test
result read after 8 minutes may not be consistent with
the original reading obtained within the 8 minute
reading period. The test results must be read within 8
minutes of sample application. Certain medications
containing opiates or opiate derivatives or
methamphetamines may produce a positive result in any
chemical or immunological assay. Additionally, foods and
tea containing poppy products and/or coca leaves may
produce a positive result. Prolonged passive smoking of
THC may also produce a positive result.
DrugTest
Services, Inc.
433 St. Luke's Drive • Montgomery, AL 36117
(334) 396-3872 • Fax: (334) 396-5872
E-Mail: eric@drugtestservices.com
Copyright © 2003 All Rights Reserved.
DrugTest Services, Incorporated
