Pilot PT Program for Alternative Matrices: Cannabinoids

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Pilot PT Program for Alternative Matrices
Cannabinoids

• John M. Mitchell, Ph.D.
• DTAB meeting
• June 4, 2002
• Note See DTAB meeting transcript for verbal
  comments

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Evaluation of Analytical Values Reported for
Cannabinoids

• Only confirmatory test values
• for Urine, GC/MS
• quantitations are in ng/mL (ppb)
• for Hair, mostly GC/MS/MS (only 1 or 2 by GC/MS)
• quantitations are in pg/mg (ppt)
• for Oral Fluid, some GC/MS and some GC/MS/MS
• quantitations are in ng/mL (ppb)

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• Variance
• Industry agreed-upon cutoffs
• Means of values reported by the participating
  laboratories
• Calculated for samples with three or more values
• Annotated above each histogram bar
• Percent coefficient of variation
• Mathematical indicator of the variation

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• Performance around cutoffs
• Graphs of reported values from each lab versus
  the mean value
• Containing 20 and 50 quantitation ranges
• Relative position of cutoff
• Distribution below the cutoff

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Source of Analytical Values

• 2 Urine Maintenance PT Cycles for all labs
  currently certified in the NLCP
• 4 Hair Pilot PT Cycles
• The 6 labs that completed all 4 cycles
• 3 Oral Fluids Pilot PT Cycles
• The 9 labs that completed all 3 cycles

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Cannabinoid Confirmation Methods

• Urine - GC/MS
• Hair- GC/MS (EI and NCI), GC/MS/MS
• Oral Fluids- GC/MS (EI and NCI), GC/MS/MS

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Confirmation Methods for Cannabinoids

• xxxx Did not test

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Confirmation Methods for Cannabinoids

• xxxx Did not test

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Future Plans

• Complete in-depth evaluation of confirmation
  testing for other analytes
• Additional pilot PT cycles to clarify performance
  issues around cutoffs (e.g., precision and
  accuracy)
• Complete in-depth evaluation of immunoassay tests
• Additional pilot PT cycles to clarify performance
  issues around cutoffs (e.g., precision, and
  specificity)

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Future Plans (cont.)

• POCTesting
• Evolve cutoffs and standards of testing