Drug tests are pretty unreliable. You have to choose a test that is for the DOC and even then they can manipulate it - not to mention that some drugs wont show up unless they have used in 24 hours. My AS admits that he can get around most drug tests - pot is the hardest to hide because it stays in the system longer so he would use other things that he knew wouldnt show up. Blood tests are much more reliable than urine but they take much longer to get back and are more expensive.