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Advanced Urine Drug Testing

NOAH Clinical Laboratory utilizes the latest technology available to detect a wide array of drugs and metabolites in urine samples. We employ modern LC-MS/MS instrumentation to provide results in the quickest, most accurate fashion possible. Use of confirmatory quantitation methods provide many benefits when compared to point-of-care (POC) testing and screening assays.

Benefits of Quantitative Confirmation Analysis

Applications of toxicology testing include:

  • Determining whether patients have recently taken their prescribed medication
  • Discovering if non-prescribed medications or illicit drugs have been used
  • Monitoring compliance of medications with a high abuse potential
  • Prevention of misuse, addiction, or diversion

Benefits of Quantitative Confirmation Analysis with LC-MS/MS

Drug Screen Limitations

  • Lack specificity
    • Drug classes vs. individual drugs
    • Ex: Opiates vs 6-monoacetylmorphine
      (heroin metabolite)
  • Cross reactivity
    • High concentrations of other drugs can yield false positives
    • Ex: DRI Methadone EIA false positive with Tapentadol and metabolites
  • Lack sensitivity
    • Cutoffs typically lower
    • Ex: Opiate cutoff = 300 ng/mL vs 50 ng/mL
  • Not comprehensive
    • Covers approx. 20 drug classes and without focus on metabolites
    • Ex: Detection of noroxycodone (oxycodone metabolite) would indicate biological metabolism, not spiking of oxycodone into the sample
    • Semi-quantitative at best

Interpretation of a Positive Drug Screen

  1. Patient is compliant and took the prescription as directed
  2. Patient added drug to the urine after collection
  3. Patient took one dose prior to collection
  4. Patient took another drug which cross- reacts with the test, i.e. a false-positive
  • Ex: Pseudoephedrine can give a “Positive” result for an amphetamine screening test

Interpretation of a Negative Drug Screen

  1. Patient is not compliant
  2. Patient did not follow dosing regimen
    • Less frequent or lower dose
  3. Drug present but below the cutoff
    • Dilute or adulterated urine
    • False-negative
  4. Test does not react with drug of interest
    • Appropriately targeted test may not be available
  5. Altered pharmacokinetic variables
    • Ultra-fast metabolizer – no parent drug present, only metabolite
    • Poor drug absorption

Strengths of LC-MS/MS Analysis

  • High specificity
    • Can differentiate between individual drugs
  • No cross reactivity
    • Utilizes 3 unique analyte properties to ID
  • Increased sensitivity
    • Cutoffs are lower than immunoassay techniques
    • Reduced false negatives
  • Comprehensive
    • Can detect many individual compounds with respective metabolites
    • Current capability is 75 analytes
  • Quantitative
    • Use of certified reference materials allow accurate quantitative values