Snus use differs from cigarette use mainly because it does not require the burning of tobacco and for that reason avoids a lot of the dangers linked to smoking cigarettes. Screening with blood may be less delicate than screening with urine. This could lead on to Wrong negatives or positives. https://images.google.es/url?q=https%3A%2F%2Ficyshop.es%2F%3Fcollections%2Fsnus