Phone interview with follow up on-site interview. Interview went very well to the point that an offer was made to join the product management team contingent upon successful background check, drug screen, etc. as I am very qualified as a firmware developer in Linux with management and product development experience (requirements def, V&V, etc). After the interview I had oral surgery and was prescribed Oxicodone for pain. Took the drug screen 4 days after surgery and had taken Oxicodone the night before the drug screen. Received a call from the testing company (LabCorp) saying that I had failed the test for THC and no failure for opiates. The interesting part is that I had not ingested any THC and the test did not indicate any opiates that I had taken for 4 continuous days, the last 12 hours before the test. The SAMSHA site says that it should have tested positive for 4-6 days! I can only conclude that either the chain of custody for the sample was violated, sample contaminated, or the test was not accurate... The only thing the testing company will do is retest the same sample which will result in the same erroneous reading. After the call I went to Walmart and bought a drug test kit and it tested positive for opiates and nothing for THC! What this proves is that we (the employment candidate) have no rights against false testimony. Be careful applying with this company and/or using LabCorp for drug screening. I lost a good job because of this!