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Measurement can be done on following samples:

  1. Blood alcohol level tested in serum or plasma or whole blood.
  2. Breath alcohol where the blood: breath alcohol ratio is 2100:1.
  3. Urine alcohol level may be estimated.


  1. Quantitation of the alcohol level is done for therapeutic or legal purposes.
  2. Alcohol level is done to diagnose alcohol intoxication.
  3. Alcohol level may be done in cases of coma, cerebral trauma, and drug overdose.
  4. To differentiate alcoholic intoxication coma from diabetic coma.
  5. This test is also done for alcoholism.
  6. This test is done on the drivers.


  1. Alcohol is Ethanol and it is readily absorbed from the GI tract.
  2. Peak level is within 40 to 70 minutes after the intake.
  3. Ethanol is metabolized by the liver enzyme dehydrogenase into acetaldehyde 90% of alcohol is metabolized in the liver.
    1. This acetaldehyde is converted into acetic acid by the enzyme Aldehyde Dehydrogenase.
  4. Ethanol metabolite acetaldehyde leads to acidosis and ketosis called Alcoholic ketoacidosis. 


  1. Once peak level is reached then it levels decreases.
  2. Ethanol depresses the CNS and ultimately may lead to coma and death.
  3. Alcohol is present in blood, urine, stomach contents, and breath.
    1. Saliva alcohol level is 9% higher than blood.
  4. Blood alcohol level of 50 to 100 mg/dL causes:
    1. Slowing of reflexes.
    2. Flushing.
    3. Impaired vision.
  5. Blood alcohol level of >100 mg/dL causes:
    1. Signs of CNS depression seen.
    2. Hypotension.
  6. Blood alcohol level >300 mg/dl is usually associated with coma.
    1. Blood alcohol level of >400 mg/dL is fatal and death may occur.
  7. urine sample and blood alcohol levels are equal, while in the saliva will have 1.2 times of blood level.
  8. The blood alcohol level  will be roughly 25 mg/dL when adult taking:
    1. An ounce of whiskey or. 
    2. 12 ounce of the bear or. 
    3. One glass of wine.
  9. Use of sedatives like barbiturates and benzodiazepines with alcohol is very dangerous and may lead to death by respiratory depression.
  10. Complication of chronic alcohol abuse:
    1. Cirrhosis of the liver.
    2. The degenerative changes in the brain.
    3. The degenerative changes in the skeletal muscles.
    4. Chronic alcoholics may have nutritional and vitamin deficiencies.


Critical Value

Blood alcohol level

 Patients presentations

100 to 200 mg/dL

Patient has emotional instability and there is a loss of critical judgment 

200 to 300 mg/dL

Patient is confused impaired balance and disorientation.

300 to 400 mg/dL

Patient is unable to walk or stand and is stuporous.

More than 500 mg/dL

Patient is in a coma with depressed respiration and slow circulation.

More than 1500 mg/dL

Patient condition is critical and may die due to respiratory paralysis.

More than 2000 mg/mL

Death due to respiratory paralysis.

Clinical effect depending on the blood alcohol concentration:

Blood alcohol concentration (%)   Clinical symptoms
<0.05% Feels Soberness and calm
0.05 to 0.1% Feels euphoric
0.1 to 0.2% Feels excited
0.2 to 0.3% Stars confusion
0.3 to 0.4% Now is stuporous
>0.4% Goes into coma and death may occur

(modified from ASCP )

Possible References Used

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