First, read the English article below.

Each state has different policies when it comes to drug testing. There are laws dictating how both new applicants and current employees can be tested. In most cases, the employer is legally allowed to administer drug tests, but only if it gives proper notice and has the test administered by a state-run laboratory. Other common requirements include the following:  All employees or applicants must be tested the same way. If an applicant is applying for a job, the fact that a drug test is part of the process must be clear from the start. In many cases, an employer isn't allowed to conduct random drug tests or blanket drug tests. In many cases, an employer can test an employee for drugs if the employer has reasonable suspicion that the employee is using (erratic behavior, inadequate work, etc.). None of the drug tests are 100 percent accurate all of the time. Urine tests are the least accurate tests, but all of them are fallible. Use this to your advantage if you end up failing a drug test. Once you've failed, there's no harm in asking for another test; say you disagree with the results and would like to take it again. While an employer who followed all of your state's laws regarding testing usually has the right to fire you if you fail a test or refuse to take one, you might be able to challenge the test if it wasn't administered properly. Review your company's policy and your state's laws to make sure they match up. If they don't you might be able to get the test thrown out, giving you an opportunity to take it again.  Check up on the lab administering and analyzing the test to make sure it's run by the state. See if your employer gave you adequate notice in advance of the test. Determine whether you experienced what you believe to be an unreasonable invasion of privacy, such as being asked to urinate in full view of someone watching. 

Now, please write a short abstract for it in Vietnamese. Abstract:
Xem các văn bản pháp luật về chính sách kiểm tra ma túy ở khu vực bạn sống. Yêu cầu được xét nghiệm lần nữa nếu bạn có cơ hội. Xem xét việc không chấp nhận kết quả xét nghiệm nếu như bạn bị dương tính.