The control line is the uppermost line appearing in each test area. The test line may or may not appear directly below the control line[C]. Once a reddish-purple control line with a clear background forms in all channels the test may be read. If no control line appears after approximately 10 minutes, consider the test invalid.
A NEGATIVE result for any single drug is the presence of two reddish purple lines, the upper control line and the lower test line. The intensity of the test lines may vary. Any line, without regard to intensity, color, or size, is a line and indicates a negitive result for that drug.
A POSITIVE result for any single drug is the presence of only one reddish purple line, the control line, and NO test line on the strip for the particular drug.
Rapid Drug Screen results are stable up to 60 minutes as long as the device is either immersed in the urine specimen or stored in a small plastic bag.