Limitations of the procedure
6
Limitations of the procedure
The analytical features can deviate at the limit of the operating
temperature range. At temperatures below +10 °C, positive test results
must not
be evaluated until 10 minutes after starting the
measurement. We recommend warming the test kit in your hands
before use. At temperatures over +35 °C and if there is a control line,
positive test results must be evaluated 3 minutes after starting the test.
Due to non-specific interactions (physiological deviation, state of
health or sample contamination), false positive or false negative
results may occur in rare cases.
The antibodies used in the Dräger DrugCheck 3000 have been
developed specifically for the detection of illegal substances (drugs/
drug classes). For the user, this means for example that the antibody
reagents of the Dräger DrugCheck 3000 are reacting with chemically
similar substances such as prescription drugs or non-prescription
medicines and are resulting in false positive results. The test has
objectively detected the chemically related substance, in the confirming
lab analysis, a corresponding illegal drug cannot be proven, however.
To achieve a confirmed analytical result, an alternative chemical
method such as GC-MS or LC-MS must be used. All the results of the
Dräger DrugCheck 3000 require professional assessment with
reference to further clinical evaluation of the test subjects. This applies
especially for positive results.
The sampling process can be closely monitored. This means that
faking the sample is unlikely. However, if faking or substitution of a
sample is suspected, dispose of the sample and repeat the test with a
new Dräger DrugCheck 3000 test kit.
7
Performance features
7.1
Influence of food and beverages
Saliva may be contaminated immediately after consuming food,
beverages or confectionery. To determine any influence of the
contamination on the results of the Dräger DrugCheck 3000, saliva
samples were taken and interpreted immediately after consuming
sample preparations:
cola, toothpaste, American cranberry juice, aseptic mouthwash, water,
cough medicine (not containing codeine), coffee, chewing gum,
chocolate, fruit tea, herbal tea, cigarettes, orange juice, full fat milk,
cough sweets containing menthol, mouthwash and tomatoes.
None of the interpretations yielded incorrect results.
As it is impossible to detect the potential influence of all foods on the
test, it is strongly recommended to observe a waiting time of
10 minutes before sampling.
10
7.2
Analytical features
7.2.1
Analytical specificity
Most
of
the
immuno-chemical
monospecific for a single analyte (drug) but they react to a group of
analytes (drug class) with a similar chemical structure (e.g. the opiate
test of the Dräger DrugCheck 3000 detects a number of different
opiates).
Therefore we do not recommend that you use the results of a Dräger
DrugCheck 3000 as a basis for (semi) quantitative statements on the
concentrations of one single analyte of a group of analytes. Data on
the analytes which can be detected with the corresponding test of the
DrugCheck 3000 as well as data on the individual concentrations
which separately generate a positive result can be found in table 1 (T1)
on page 92. The analytes found in table 2 (T2) on page 92 are not
detected at concentrations below 10,000 ng/mL by the Dräger
DrugCheck 3000.
7.2.2
Repeatability
Reproducibility studies were conducted with commercially available
reference standards and negative saliva samples. Every saliva sample
was enriched with corresponding standards to maintain the desired
concentration of the test analytes (no drugs, 200 % limit value). Every
sample was tested at every analyte concentration ten times over three
different days with the same batch of theDräger DrugCheck 3000.
Correspondence with the expected test results was achieved in 100 %
of the cases.
7.3
Analytical features
To test the analytical features of the Dräger DrugCheck 3000, native
saliva samples were collected and analysed using the Dräger
DrugCheck 3000. Some of the native saliva samples were enriched
using forensic drug standards at defined concentration values.
The analytic features of the Dräger DrugCheck 3000 are given in
table 3 (T3) on page 92. The specified analytical performance is based
on tests with the specified detection limits (cut-off).
en
detection
reactions
are
not
Dräger DrugCheck 3000