MONITORING TREATMENT -  Urine Drug Testing
Specific UDT Examples - Part A

Cocaine
  • Most useful if positive for cocaine (cross-reactivity between this screen and substances other than cocaine are nearly non-existent).  
  • Urine screens for cocaine are very accurate in detecting recent cocaine ingestion (not if taken more than 2-4 days earlier)
Amphetamines
  • Amphetamine assay is the most difficult one to interpret due to a wide variety of common medications that can produce false positive results.
THC
  • THC assay is very specific with few agents causing false positives. 
  • The only question that remains is what do you do with a positive THC screen?
Fentanyl 
  • It is not identified by either the DAU or the normal confirmation process. A special assay is required.
Oxycodone 
  • Oxycodone is metabolized to oxymorphone.  
  • For a patient taking oxycodone both may be detected via confirmation. 
  • If only oxymorphone is present it implies that the oxycodone was not taken recently.  
  • Oxymorphone metabolite of oxycodone in urine can last 1-2 days after disappearance of oxycodone in urine. 
Hydrocodone 
  • Hydrocodone is metabolized into hydromorphone. 
  • Hydromorphone is not metabolized into hydrocodone.