Does a urine test show which opiates you have taken or does it just show that there are opiates in your system?

Yes, but it depends on the test. Cheap tests usually just say if there are any drugs that this country considers illegal at this time, Other more expensive tests will tell which type of opiate, lidocane, cocaine, novacaine, pot, THC content etc.., and to what degree of concentration in your urine.