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Alcohol

Ethanol is cleared at an approximate rate of 15 mL per hour (healthy, nonalcoholic adults will clear 1 drink per hour).

1 standard bar drink (1.5 ounces of 80 proof liquor) = 1 standard glass of wine = 1 bottle of regular (4.5%) beer.

  • Alcoholics clear ethanol faster than normal.
  • Alcohol concentration is performed by headspace gas chromatography with flame ionization detection (GC-FID) (reference method to demonstrate intoxication potential in blood).
    • Serum may be submitted, but is not preferred.
    • Urine alcohol concentration is not a good indicator of intoxication.
      Note: Urine alcohol concentration depends on a number of alcoholic drinks consumed, fluid intake, and number of hours since last voiding.
blood alcohol content arrow

Widmark Equation

The Widmark Equation is a useful tool for:

  • Predicting Blood Alcohol Concentration (BAC).
  • Predicting time elapsed since the last drink.
  • Estimating how many drinks were consumed if the time of the last drink and BAC are known.
Widmark Equation

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