HelloI start nursing school this fall and went in to have all of my titers done. The lab says that they are not able to do the test due to "interfering substances" in my blood. This is after 2 different samples were taken.Has anyone else had this happen? I have not had any vaccinations recently, and I am not on any medications. I tried to google an answer but didn't find any information.I am afraid there is something wrong health wise that is causing this. Does anyone have any info at all regarding this?