Will a GC/MS test of urine give a definitive answer regarding cocaine use? No chance of false-positive?

Question

Will a GC/MS test of urine give a definitive answer regarding cocaine use? No chance of false-positive?

Answer 1

GC/MS is largely foolproof for drug testing. If the drug (or metabolite) is present, it will find it. False positives are possible (largely due to operator error). But if the machine is run properly, the chances of a false positive are extremely low.

Standard drug screens use a GCMS test to rule out false positives on conventional dip-stick tests for drugs in the urine.