Results Interpretation


 

Drug/Drug Class

Detection Time in Urine

Test to Order

Expected Results

Comments

Opiates-Natural

Codeine

1 to 3 days

 

Opiate Immunoassay + GC/MS or LC/MS Opiates

Opiates Immunoassay – Positive

 

GC/MS or LC/MS - Codeine (possibly morphine and hydrocodone)

  • "Opiate" immunoassays detect morphine and codeine, but do not differentiate which is present. Confirmatory testing should be performed to reliably identify which drug(s) is/are present.
  • Codeine is metabolized to morphine and in small amounts to hydrocodone
  • Morphine is metabolized to hydromorphone

 

Morphine

Opiates Immunoassay – Positive

 

GC/MS or LC/MS - Morphine (possibly hydromorphone)

Opioids-Semisynthetic

Hydrocodone

1 to 3 days

Opiate Immunoassay + GC/MS or LC/MS Opiates

Opiates Immunoassay – Positive

 

GC/MS or LC/MS – hydrocodone, possibly hydromorphone

  • Opiate immunoassays may detect semisynthetic opioids depending on the cross-reactivity pattern; a negative result does not exclude use of semisynthetic opioids and a confirmatory test should be performed to very compliance with prescribed semisynthetic opioids.
  • Hydrocodone is metabolized in small amounts to hydromorphone
  • Oxycodone is metabolized to oxymorphone

Hydromorphone

Opiates Immunoassay – Positive

 

GC/MS or LC/MS -  hydromorphone 

Oxycodone

Opiates or Oxycodone Immunoassay + GC/MS or LC/MS Opiates

Opiates Immunoassay – Positive, dose > 100 mg/day

 

Oxycodone Immunoassay – Positive

 

GC/MS or LC/MS – oxycodone, possibly oxymorphone

Oxymorphone

Opiates or Oxycodone Immunoassay – positive

 

GC/MS or LC/MS -  oxymorphone

Opioids-Synthetic

Fentanyl

1 to 3 days

GC/MS or LC/MS Fentanyl

GC/MS or LC/MS – fentanyl and norfentanyl

Current "opiate" immunoassays do not detect synthetic opioids. As such, confirmatory tests (GS/MS or LC/MS/MS) are required to identify these drugs. If the purpose is to document adherence to prescribed treatment, the laboratory can be instructed to remove the cut-off concentration so that the presence of lower concentrations can be identified.

Meperidine

GC/MS or LC/MS Meperidine

GC/MS or LC/MS – normeperidine, possibly meperidine

Methadone

3 to 7 days

Methadone Immunoassay + GC/MS or LC/MS Methadone

Methadone Immunoassay – positive

 

GC/MS or LC/MS – methadone and EDDP

Miscellaneous

Amphetamines

2 to 3 days

Amphetamines, Methamphetamines or MDMA Immunoassay + GC/MS or LC/MS Amphetamines

Amphetamines, Methamphetamines or MDMA Immunoassay -  see comments

 

GC/MS or LC/MS Amphetamines - Amphetamines, Methamphetamines or MDMA

  • Amphetamine immunoassays are highly cross-reactive so results should be interpreted cautiously, and may require consultation with the lab
  • Amphetamine assays may detect other sympathomimetic amines (e.g., ephedrine, pseudophedrine or selegeline.
  • Confirmatory testing should be performed to identify which amphetamine is present

Barbiturates

1 to 3 days (short-acting); up to 30 days with long-acting

Barbiturates Immunoassay

See comments

Immunoassays readily detect barbiturates as a class of drugs. Specific barbiturate identification can be accomplished by utilizing confirmatory methods

Benzodiazepines

1 to 3 days (short-acting); up to 30 days with long-acting

Benzodiazepine Immunoassay

See comments

  • Detection of benzodiazepines in the urine by immunoassays is primarily based on detection of oxazepam and nordiazepam, the primary metabolites of many of the benzodiazepine drugs
  • Immunoassays are unable to distinguish between individual benzodiazepines

Buprenorphine

2 to 3 days

GC/MS or LC/MS Buprenorphine

GC/MS or LC/MS - Buprenorphine or norbuprenorphine

 

Cocaine or benzoylecgonine

2 to 4 days

Cocaine Metabolites Immunoassay

Cocaine or benzoylecgonine

The cocaine immunoassay is highly sensitive for cocaine use; other topical anesthetics with the suffix "caine" (e.g., lidocaine) will not result in a positive immunoassay test

Marijuana

2 to 4 days, up to 30 days with chronic heavy use

Cannabinoids (THC) Immunoassay

GC/MS or LC/MS THC

Cannabinoids Immunoassay – see comment

 

GC/MS or LC/MS – THC

Urine cannabinoid immunoassays are usually optimized for the detection of carboxy-THC, but also react with other cannabinoids present in the urine. Because of this cross-reactivity, immunoassay results are expressed in terms of "total cannabinoids"