Dräger DrugTest 5000 Technical Manual page 52

Appendix
9.1.7 Quality control
A quality check at regular intervals belongs to good analytical
practice and is also possibly required by local authorities.
Internal control: An integrated process control is performed
during every analysis. A control signal is generated when a test
was properly developed. If this control signal fails to appear,
the Analyzer will not evaluate the corresponding analysis.
External control: Based on the test properties a quality control
can be conducted on site by using a drug-free sample and
processing it. The result for all analyses for this sample must
be NEGATIVE. Information on commercial positive controls for
this test are available from DrägerService
9.1.8 Confirmation of results
The Dräger DrugTest 5000 test system is a qualitative
measuring system to detect searched substances or their
metabolites which are contained in the sample in excess of
certain concentration limits (cut-off) and therefore delivers only
a preliminary analytical result (screening method). To obtain a
confirmed analytical result a second sample must be taken and
analysed by another more specific method in an authorised
laboratory. Gas chromatography/mass spectrometry (GC/MS)
is the preferred method used in most cases. When using saliva
samples, the second sampling should be done with the Dräger
DCD 5000 (order no. 83 19 910). See "Analysis method for
confirmation" on page 53.
9.1.9 Limitations
The Dräger DrugTest 5000 test kit was designed for the
analysis of samples collected with the test kit's sampler.
The use of liquids other than those specified in the
Instructions for Use of the respective test kit or samples
absorbed by another method can lead to incorrect results.
A positive result during the test will only show that the
substance concentration lies above the limiting value of the
test kit. A negative result can indicate that the sample is
either free of drugs or their concentration lies below the
limit.
The reagents used in the test kits are especially meant for
the detection of the specified substances. Nevertheless,
structurally similar prescribed and over-the-counter drugs
can react with the reagents and cause false positive
results.
Due to the properties of immunoassays cross-reactive
substances or unspecified interactions can interfere with
the test and produce false results. Technical errors and
procedural errors can also contribute to incorrect results.
Rare false results may occur as a result of non-specific
interactions (physiological variation, state of health,
contamination of the sample with food or other substances,
etc.) (see also "interfering substances"). Technical errors
and procedural errors can also contribute to false results.
The taking of samples should be closely monitored. If there
is a suspicion that the sample collection was tampered
with, repeat the test with a new test kit.
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9.1.10 Interfering substances
Rare false results may occur as a result of non-specific
interactions
contamination of the sample with food or other substances,
etc.) (see also "interfering substances").
Each test kit panel type was tested for the interaction with
various interfering substances. Detailed information on
possible interactions of interfering substances with a specific
test kit can be found in the Instructions for Use of the
respective test kit.
9.1.11 Specificity
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.
The reagents used in the test kits are especially meant for the
detection of the specified substances/substance groups.
Nevertheless, prescribed and over-the-counter drugs with
structurally similar active agents can cross-react with the
reagents and cause false positive results.
In order to provide support for users during the evaluation of
positive results of the analysis, test kits were subjected to
broad investigation of their specificity and cross-reactivity. In
the Instructions for Use of the test kits you will find tables and
charts with the substances examined per detection reaction
and the concentrations where a positive analysis result of this
detection reaction is possible if they are exceeded.
Furthermore, it should be borne in mind that the presence of
several similar substances whose individual concentrations
are below the limit can together produce a positive result.
9.1.12 Accuracy
In order to verify the clinical performance of the test kits on site
results were compared with the results of the appropriate
secondary samples. The results of these comparative
measurements can be found in tabular form in the Instructions
for Use of the test kits.
(physiological variation,
Dräger DrugTest 5000 Testsystem
state of health,