Preliminary positive is the immediate indication of the presence of a pre-determined substance (drug) in a urine specimen. A preliminary positive result indicates a degree of uncertainty as the test has been performed using a sensitive, but not quantitative assay. In order to remove this uncertainty, a confirmation test is recommended.
Confirmation test is a qualitative test generally conducted by a laboratory using GC/MS or LC/MS, to identify the specific amount of drug metabolite that was detected in the initial screen.
Gas chromatography-mass spectrometry (GC/MS ) is a method that combines the features of gas-liquid chromatography and mass spectrometry to specifically identify different substances within a test sample.
Liquid chromatography-mass spectrometry (LC-MS) is an analytical chemistry technique that combines the physical separation capabilities of liquid chromatography (aka HPLC) with the mass analysis capabilities of mass spectrometry . LC-MS is a powerful technique used for many applications.
The control line in an ABMC device is the uppermost line appearing in each test channel. If one of the control lines does not appear, the test is invalid and the results cannot be used or relied upon.
The test line in an ABMC device is the reddish-purple line adjacent to the drug name. If both the control line and test line are present the test result for the corresponding drug is negative.