Usually it takes 3 days for the results to come bac. If its a DOT qualified job the MRO has to try and contact you 3 times in a 24 hour period.For a non DOT job I'm not sure.If it was a negative dillute they would just contact the employer.If you get a negative dillute try and see if the employer will let you take another test. Tell them your dr requested you to drink as much fluids as possible. I have to do that when I have a blood draw because my blood comes out like mollasses