How the First Check® Home Drug Test works
The First Check® Home Drug Test Thin Layer
Chromatography process takes place on each of the test strips on
the Test Lid. The process works by exposing the urine sample to
special chemical reagents within the test strip in a specific order
and at a specific speed.
- When the First Check® Test Lid is
secured to the top of the cup and the cup is tilted into its legs,
the urine in the cup comes into contact with the First Check test
strips on the Test Lid.
- The absorbent material of each test strip
carries the urine sample across the strip at a specific
- First, the urine sample encounters special
molecules and carries them further up the test strip where they
will interact with drug-specific antibodies that only react to
metabolites for the specific drug being tested.
- If the urine sample does not contain the
specific drug metabolites being tested for, the special molecules
react with the antibodies to turn a color.
- When the molecules turn color, the test is
Negative for the drug being tested for.
- If the urine sample does contain the specific
drug metabolites being tested for, the molecules do not turn
- When the molecules do not turn color, this
indicates a Preliminary Positive Result for the drug being tested
- Finally, the sample reaches the Control Line at
the top of the test strip where a reagent makes the molecules turn
color to indicate that the test is working properly.
- When the Control Line turns color, it means the
test is working properly.
The First Check®
Home Drug Test is considered a
“screening test.” First Check recommends all Preliminary Positive
Results be sent to our laboratory for free confidential
confirmatory testing. Gas chromatography/mass spectrometry (GC/MS)
is considered the gold standard in laboratory testing for most
First Check customers who have received a Preliminary Positive
Result can use the Pre-addressed Mailing Box included in the First
Check Home Drug Test kit to send the urine sample to the lab for
free confidential analysis. The First Check Lab is one of the
nation's premier forensic drug testing facilities that uses the
most advanced processes and equipment, offering expert
toxicological review to produce the most accurate result possible –
all while maintaining strict confidentiality.
to learn more about
how to use the test.