Is there any test that docs can perform to tell the differences of what kinds of opiates you have in your system?

Pain: Absolutely ...We can even pick up metabolites from heroin. All we need is a little bit of ur urine :).

Yes: Yes, although it can take a while. Most clinics and doctor's offices use an on-site urine or saliva screen for certain drugs and medications. What is gained in having quick results is occasionally lost with accuracy. Thus, sometimes the urine is sent out to a lab-- it is there that they can tell the difference between the different opiates among many others. The lab very rarely makes errors.