Open question: Saliva adds to the test question ht?

My friend has straight itself applied for a job and today asked her him to waive something clerical work before it begins its attempt on Monday. When he came there, they explained to him that he must take a drug test, which was happy he, to accomplish. The drug test was a mouth and as it terminated, was very weak the last line (this line, which is for Benzedrin). Why did this happen, if my friend never saw even the material let alone, it is taken and the line should have completely disappeared, if it were a positive for Benzedrin? Are these tests as exact? They explained to him, in order to accomplish another test on Monday, because he explained that he did not do drugs and I think that they believed him. How can we stop this, which happens again on Monday? Also I none it has no drugs done, because ive, which is with him and I to think that I was considered of, if he were on everything, thus which wrongly went? Owing to x