Actually it is exactly that...the chain of custody was broken! The chain of custody requires that the donor be present until the bag is sealed. The donor is supposed to sign the form ONLY AFTER the sample bottle has been sealed in their presence. It seems the person knew the procedure was not being done correctly at the time. What he/she should have done was brought that to the attention of the collector and refused to sign the form until the specimen was sealed.
I do have one question....if the specimen was not sealed in the person's presence then how did their initials get on the bottle seal? The lab will not accept a sample without an initialed seal.
I am not accusing anyone because I don't know this person but I will say I have been a DOT certified drug screen collector for over 20 years. I have heard every excuse in the book! I have believed some of them and then they either admit it later on or test positive again at a later date. Never in my career has anyone had a "false positive". Keep in mind if this is a DOT certified lab they do not test at low levels that would pick up some things like energy drinks, herbs, cold meds etc. These things would be ruled out at a higher level.
Unfortunately this person is out of luck but may have learned a valuable lesson. Never sign off on a drug screen until the bottle is sealed in your presence!