PharmChek® drugs of abuse patch uses sweat as the specimen source. It provides an alternative to urine collection and offers a number of advantages. Because the sweat patch is worn on the skin for up to 10 days or longer, it not only acts as a deterrent to continued drug use, but also increases the window of detection to include any period when it is worn. With sweat testing – unlike urine – the parent drug, as well as the drug metabolite, can typically be detected. Therefore, it is easier to identify which drug was actually taken.