Blood Alcohol

Results

A blood alcohol test measures the amount of alcohol (ethanol) in your body. Some states have no set limit for legal intoxication. But the National Highway Traffic Safety Administration (NHTSA) recommends that all states set the legal definition of intoxication as the point when the blood alcohol concentration (BAC) exceeds 0.08 (which is equivalent to 80 mg/dL or 17 mmol/L).

Blood alcohol

Normal:	No alcohol is found in the blood.
Abnormal:	Any alcohol is found in the blood.

Most states define legal intoxication as having a blood alcohol concentration (BAC) of 0.08 to 0.10 or greater. Many states define intoxication as a blood alcohol concentration (BAC) lower than 0.08 for people under age 18.

Effects of drinking alcohol

Having any amount of alcohol in the blood can cause poor judgment and slowed reflexes.

Effects of drinking alcohol

Number of drinks per hour*	Estimated blood alcohol concentration (BAC)†	Observable effects†
1–2	0.02	Relaxation, slight body warmth
3	0.05	Sedation, slowed reaction time
6	0.10	Slurred speech, poor coordination, slowed thinking
12	0.20	Difficulty walking, double vision, nausea, vomiting
18	0.30	May pass out, tremors, memory loss, cool body temperature
24	0.40	Difficulty breathing, coma, possible death
30	0.50 and greater	Death
*1 drink = 1.5 fl oz (45 mL) liquor (80 proof) or one glass [5 fl oz (150 mL)] wine or one glass [12 fl oz (360 mL)] beer.
†BAC and the effects of drinking alcohol vary from person to person and depend upon body weight, the amount of food eaten while drinking, and each person's ability to tolerate alcohol.

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Author:	Jeannette Curtis	Last Updated: May 9, 2008
Medical Review:	Kathleen Romito, MD - Family Medicine R. Steven Tharratt, MD, MPVM, FACP, FCCP - Pulmonology, Critical Care, Medical Toxicology
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