My 18 year-old daughter was given a urine drug test at a lab. She was required to perform this test in a single rest room, with the door open and visible to the adjacent hallway. The female attendant was standing outside this door and there were at least two male employees in a room next door. Will this be considered a privacy issues, were her rights violated? She stated she felt humiliated.
Without knowing in what state you and your daughter reside, it is difficult to determine whether any state or local laws were violated by the manner in which the laboratory conducted the drug test. It also has to be assumed that your daughter is not employed at a business with a unionized labor force, as union contracts generally have strict guidelines on how and when drug tests can be administered.
Having said that, if the description provided in the question is accurate, then the procedure may have violated your daughter's privacy. The mere act of submitting to a urine test is considered by many people to be a humiliating experience, but private companies, barring labor agreements with a union, are free to require drug testing of employees. There are, however, standardized procedures for how urine tests are to be administered. Vital to the integrity of the test is the chain of custody -- in other words, how the urine sample is handled once the employee hands it over to a lab assistant or other designated person. Also, the temperature of the urine must be properly maintained to ensure an accurate reading. So, it was correct for a female lab employee to be in the room with your daughter.
What could be argued to have been inappropriate is the "fact" of the door being open to a hallway. There is no reason for the door to have been open. Depending on the size and configuration of the restroom, the lab employee should have been in the room, in the event the room included an enclosed toilet for privacy, or, conversely, if the restroom was a small room with only one toilet, then the attendant should have waited outside the closed door, once establishing that your daughter was not carrying a bag or purse in which a fake urine sample could have been concealed.