What is the standard drug test ie..Basic Immunoassay vs. GC-MS/Etc. used by the VA Southern Nevada HCS in house/hospital for initial test? Not the forwarded test for confirmation to a reliable test. But the first test in the hospital itself. I suspect it is the cheap inaccurate one for when it comes to Oxycodone. Because I came up negative when I should not have. I have already learned why. Now I'm trying to learn exactly what test was used for confirmation of my suspect.