Key For Reading Drug Test Results

  • Control line (top line) = test valid
  • No control line = test invalid (repeat)
  • Test line= test negative
  • No test line = test positive

Invalid Results

The figure below is an example of an invalid test for THC. All the other drug strips shown are negative. Each drug strip is to be read individually.

Positive Results

The following is an example of a positive test result for cocaine and a negative result for all other drugs in the cup.

Line Intensities May Vary

Notice in the photo that the test lines on the bottom are not as dark as the control lines on top, and that even the test lines on the bottom vary in intensity.