There are two Test Lines located on both sides of the Control Line. The Control Line is weak and visible all the time and serves as a treshold for comparing both Test Lines’ intensities.
The Control Line acts as the limits of detection of the antibiotics within the milk. Comparing the intensity of the Test Lines with that of the “CTRL” line allows interpretation of the dipstick’s results.
When “TEST” lines, either bottom (Beta Lactam) or top (Tetracycline) are more visible than the “CTRL” line, the sample is NEGATIVE and contains a lower antibiotic concentration than the limits of detection.
When the “TEST” lines are as visible/ less visble than the “CTRL” line, the sample is considered to be positive and contains an antibiotic concentration that is equal to or higher than the detection limits.
No “TEST line indicates a HIGHLY POSITIVE sample for both Beta Lactams and Tetracycline compounds.
When hesitating, you should regard the sample as positive and confirm by having a second interpretation within 15 minutes.
