I am a CNA at a hospital. Where I work they give out random drug tests. I started working this year and got a urine and blood test done for my pre employment qualifications. I was wondering when do they usually give out those random drug tests in hospitals? Also.. if you pass the urine test, do they still do the blood test to double check for drugs in your blood system.. And do they warn you when you will have to take the test.. any info on this would be great