BIOLOGICAL ASSESSMENT

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BIOLOGICAL ASSESSMENT
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INDICATORS OF EXCESSIVE ALCOHOL USE

• Blood work
• Gamma-glutamyltransferase (GGT)
• Most common and reliable indicator of heavy
  drinking
• An enzyme produced by the liver. An indicator of
  early liver cell damage.
• Limited by the fact it will be elevated for
  several non-alcohol related disease states and
  its interaction with several medications.
• Takes 2-6 weeks of abstinence to return to normal
• Aspartate aminotransferase (AST)
• an enzyme released into the blood when certain
  organs or tissues, particularly the liver and
  heart, are injured
• Carbohydrate-deficient transferrin (CDT)
• CDT is abnormal variant of transferrin, a blood
  protein that functions in the transport of iron
  through the bloodstream
• CDT levels increase in response to alcohol
  consumption (mechanism unclear)
• Mean corpuscular volume (MCV)
• Measure of the average size of red blood cells
• Increased size marker of excessive alcohol intake

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DRUG TESTING
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SCREENING TESTS FOR DRUGS OF ABUSE

• relatively inexpensive screening tests (10-20)
  to detect broad spectrum of drugs
• THIN-LAYER CHROMATOGRAPHY (TLC)
• specimen placed on plate of glass plate placed
  into a particular solvent drugs interact with
  the solvent and thin-layer coating producing
  different colors and causing migration to
  different areas because of polarity

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• IMMUNOASSAY
• specific drug antibodies and specific tagged
  drugs added to the urine sample antibodies seek
  out binding sites on the tagged drugs and the
  other drugs in the sample examination of the
  percentage of tagged drugs bound by antibodies
  tells you about the presence and amount of real
  drug in the sample that came from the person
  supplying the urine
• e.g. if you added 10 tagged cocaine molecules to
  the sample and 10 antibodies and the persons
  urine contained no cocaine, then most of the
  tagged cocaine will have antibodies attached
• However, if the persons urine contained 100
  cocaine molecules then only a small portion of
  the tagged cocaine would have antibodies

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antibody
tagged cocaine
cocaine
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CONFIRMATION TEST FOR DRUGS OF ABUSE

• Screening tests tend to be oversensitive, which
  is why confirmation of positive results is
  recommended. Results can be confirmed by GAS
  CHROMATOGRAPHY/MASS SPECTROMETRY(GC/MS)
• Sample is vaporized and put through long glass
  tubing, the sides of which have varying polarity.
  This causes separation of the gas molecules into
  different (but homogeneous) groups. (Gas
  Chromatography)
• Each group of gas molecules is then subject to
  electron beam bombardment so as to determine the
  exact mass and quantity of the molecules. (Mass
  Spectrometry). This allows the molecules to be
  identified.

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Breathalyzers for alcohol
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DRUG TESTING CONSIDERATIONS

• Which Body Substance?
• Urine
• most commonly used
• highest concentrations of most drugs in urine
  because of the concentrating function of the
  kidneys
• Comparatively cheap good at detecting substances
  that are slowly metabolized (marijuana, PCP,
  benzodiazepines)
• Somewhat invasive poor at detecting quickly
  metabolized substances (alcohol, cocaine)
  subject to tampering
• Blood
• Invasive
• No real advantages over urine (lower drug
  concentrations)
• Sweat
• Superior for substances with short half-lives
  (cocaine)
• unable to detect some substances (e.g., alcohol),
  is insensitive for other substances (e.g.,
  marijuana), and requires compliance in wearing a
  sweat-absorbing patch for a period of time

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• Saliva
• inferior to urinalysis because drug
  concentrations are lower and retained for shorter
  period of time
• noninvasive, quick, inexpensive, less prone to
  tampering (use dipstick)
• Breath
• Accurate for alcohol only
• Noninvasive, inexpensive, quick, portable
• To avoid false positives should not smoke or
  drink for at least 15 minutes prior
• Hair
• Can provide history of drug use for up to a year
• Unable to detect drug use for the 3 days prior
• expensive, do not screen for all substances

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DRUG ELIMINATION TIMES (urine)
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PROS CONS OF DRUG TESTING

• Advantages
• Improves validity of assessment
• most valid procedure for establishing substance
  use is by means of a positive report by the
  person or a positive result from biochemical
  testing
• Improves validity of self-report, especially in
  noncooperative populations (adolescents,
  parolees, etc.)
• effective way of reducing drug use in sports
• effective way of reducing drug use in the
  workplace
• prior to institution of testing in 1981, 48 of
  U.S. armed services personnel used illegal drugs
  after 3 years of testing fewer than 5 were found
  to be using
• 6 of Alberta employers do this (mostly in
  Manufacturing 25 Telecommunications 26)

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• Disadvantages
• cost
• Some substances are present in such minute
  quantities (e.g., LSD) they are virtually
  impossible to detect
• Problems with false positives and false negatives
  (latter because of quick metabolism of many
  substances)
• does not measure quantity or chronicity
• potential invasion of privacy, because GC/MS can
  detect prescription drugs (e.g., antidepressants)
• Can potentially be circumvented by tampering

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TAMPERING

• DILUTION OF URINE PRIOR TO PROVIDING URINE SAMPLE
• e.g., drink several glasses of water prior to
  test and/or use diuretic (coffee, cranberry
  juice)
• -gttest specific gravity
• -gtexamine colour
• -gttest creatinine levels
• DRINKING COMMERCIAL CLEANSING PRODUCTS PRIOR TO
  PROVIDING URINE SAMPLE
• e.g. Test Pure contains diuretics B vitamins to
  produce yellow urine creatinine lots of fiber
  to redirect fat soluble metabolites to colon
  rather than bladder (only useful for infrequent
  drug use)
• -gttest frequently( these products too expensive
  for the drug abuser to use frequently)

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• ADDING SOMETHING TO THE URINE SAMPLE TO MAKE THE
  DRUGS DIFFICULT TO DETECT
• hot water
• -gttest temperature
• -gttest specific gravity
• -gtexamine colour
• -gtobserve the person urinating
• -gttest for other drugs that should be there
  (e.g., caffeine, rx medications)
• commercial additives (Klear, UrinAid) or
  household additives (bleach, salt, liquid soap)
• -gttest pH (will detect bleach and vinegar)
• -gtexamine for bottom residue
• -gtexamine for clarity (soap will be cloudy)
• -gtexamine for specific gravity (salt)
• -gtobserve the person urinating
• URINE SUBSTITUTION

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LAB TESTING PROTOCOL

• Observe person urinating
• OR
• Send person to bathroom with no purses, coats,
  etc.
• Immediately test sample for temperature
• Immediately examine for clarity, colour smell
• Test sample for pH, creatinine, specific gravity
• Test sample for caffeine or other known rx drugs
• Test frequently