Originally Posted by FakeBoobsRule
Are you familiar with immunoassay? Many drug tests use immunoassay first since it is cheaper than GC/MS, then if a positive shows up, it is confirmed with GC/MS because it is more accurate and can eliminate the few false positives that may occur. So the + I think is referring to confirmation by gc/ms and not gc/ms as being the first test conducted. SAP stands for substances of abuse panel and the 50 only referes to marijuana. Most of the other thresholds are set and the requester of the test can choose from 100, 50, or 20 for THC.