NEGATIVE: Two colored lines appear, one in the control region and another one in the test region. No matter the color intensity of the test line is weaker or stronger than that of the control line,the test result is negative, which indicates that the free drug is absent or less than the detection level of the test.
POSITIVE: Only one colored line appears in the control region with no apparent line in the test region. The test result is positive, which indicates that the free drug is present in the urine at or exceeding the detection level of the test.
INVALID: The test is invalid if the control line is not visible regardless of the presence or absence of the test li