- Alcohol level can be estimated in blood, breath and in saliva.
- When collecting blood then don’t clean the site with alcohol. Clean the site with an alcohol-free disinfectant like benzalkonium chloride.
- A blood test is the best sample for the estimation of alcohol.
- Blood sample in a living patient may be whole blood, serum or plasma.
- Serum and blood alcohol ratio is 1:14.
- Blood in a cadaver is taken from the aorta.
- The blood must be capped to avoid evaporation of alcohol.
- Collect blood in sodium fluoride or potassium oxalate.
- Use alcohol-free disinfectants.
- Alcohol is volatile so capped the bottle to avoid evaporation.
- Can store the blood when it is properly sealed for 14 days at room temperature or at 4 °C with or without preservative.
- For longer storage or nonsterile postmortem, specimen use the preservative, sodium fluoride.
Measurement can be done on the following samples:
- Blood alcohol level tested in serum or plasma or whole blood.
- Breath alcohol where the blood: breath alcohol ratio is 2100:1.
- Breath alcohol = g/210 L
- This above value is equal to blood alcohol g/dL.
- Before performing the breath test wait for 15 minutes to rule out:
- Alcohol may be present in the mouth in case of recent drinking.
- Vomiting containing alcohol rich gastric fluid.
- Alcohol-containing mouth wash.
- Salive may be used where the concentration of alcohol is 9% higher than that in the whole blood.
- This is an easy and noninvasive method.
- Urine alcohol sample is noninvasive and easy to collect the sample.
- During the post-absorptive stage after alcohol intake, the concentration of the alcohol in the urine is roughly 1.3 times that in the blood.
- This is variable, so better empty the bladder and then collect urine after 20 to 30 minutes.
- It can detect ingestion of alcohol within the previous 8 hours.
- Quantitation of the alcohol level is done for therapeutic or legal purposes.
- Alcohol level is done to diagnose alcohol intoxication.
- Alcohol level may be done in cases of coma, cerebral trauma, and drug overdose.
- To differentiate alcoholic intoxication coma from diabetic coma.
- This test is also done for alcoholism.
- This test is done on the drivers.
- Alcohol is Ethanol and it is readily absorbed from the GI tract.
- Peak level is within 40 to 70 minutes after the intake.
- Ethanol is metabolized by the liver enzyme dehydrogenase into acetaldehyde.
- 90% of alcohol is metabolized in the liver.
- This acetaldehyde is converted into acetic acid by the enzyme Aldehyde Dehydrogenase.
- Ethanol metabolite acetaldehyde leads to acidosis and ketosis called Alcoholic ketoacidosis.
- Ethanol converted to acetaldehyde.
- Headache, flushing, and hangover are due to acetaldehyde before it is metabolized to acetate.
- Once peak level is reached then its level decreases.
- Ethanol depresses the CNS and ultimately may lead to coma and death.
- ≤50 mg/dL = Euphoria and decreased inhibitions.
- 100 to 300 mg/dL = Incoordination and decreased orientation.
- >400 mg/dL = Coma and death.
- CNS dysfunction is more pronounced when:
- Ethanol concentration is increasing (absorptive phase).
- Than when it is declining (elimination phase).
- Alcohol blood concentration level of 100 mg/dL has been established a limit for car/truck driving in most of the states in the United States.
- While in 17 states this limit is 80 mg/dL.
- When ethanol is used with other CNS-depressant drugs, then ethanol exerts potentiation or synergistic depressant effect.
- Alcohol is present in blood, urine, stomach contents, and breath.
- Saliva alcohol level is 9% higher than blood.
- The blood alcohol level of 50 to 100 mg/dL causes:
- Slowing of reflexes.
- Impaired vision.
- The blood alcohol level of >100 mg/dL causes:
- Signs of CNS depression seen.
- Blood alcohol level >300 mg/dl is usually associated with coma.
- The blood alcohol level of >400 mg/dL is fatal and death may occur.
- The urine sample and blood alcohol levels are equal, while in the saliva will have 1.2 times of blood level.
- The blood alcohol level will be roughly 25 mg/dL when adult taking:
- An ounce of whiskey or.
- 12 ounce of the bear or.
- One glass of wine.
- Use of sedatives like barbiturates and benzodiazepines with alcohol is very dangerous and may lead to death by respiratory depression.
- Chronic use of alcohol may lead to:
- Cirrhosis of the liver.
- The degenerative changes in the brain.
- The degenerative changes in the skeletal muscles.
- Chronic alcoholics may have nutritional and vitamin deficiencies.
- The rate of elimination of ethanol from the blood circulation.
- Men = 11 to 22 mg/dL/ hour.
- Average level is = 15 mg/dL/hour.
- Women = 11 to 22 mg/dL/hour.
- Average level is = 18 mg/dL/hour.
- The elimination rate also influenced by the drinking habit.
- For example = Alcoholics have an average elimination rate of about 30 mg/dL/hour.
- Alcohol or ethanol intake effects on the body are:
- Ethanol ingestion leads to hypoglycemia and ketonemia because of inhibition of gluconeogenesis.
- Lactate accumulates and competes with uric acid for excretion through the kidney. So serum uric acid level is increased.
- When alcohol is taken with fatty meals, leads to hypertriglyceridemia and this may persist for more than 12 hours.
- In case of moderate intake of alcohol for one week leads to increased serum triglyceride >20 mg/dL.
- The toxic level of alcohol stimulates the release of:
- Increased intake of alcohol leads to:
- The decreased plasma testosterone level in the men.
- There is an abnormal pituitary, adrenocortical and medullary function.
- Alcohol ingestion after metabolized leads to acetaldehyde formation which causes damage to mitochondria of hepatocytes and H+ leads to fat accumulation.
- This system increases in chronic alcoholism and increased the level of acetaldehyde and acetate.
- The acetate enters the acetyl-CoA cycle and leads to increased synthesis of fatty acids and the end result is fatty liver.
- Ethanol leads to diuresis by inhibiting the ADH from the posterior pituitary.
- It also inhibits the secretion of the Oxytocin from the posterior pituitary. So this can be used in stopping uterine contraction in the premature labor.
- Complications of chronic alcoholism are:
- Cardiovascular diseases.
- Seizures like epilepsy.
- Increased risk for infections like tuberculosis, HIV and pneumonia.
- Alcoholic neuropathy.
- gastritis and pancreatitis.
- Negative in the blood or any sample.
- <10 mg/dL = considered negative.
- <20 mg/dL = considered negative by the US transportation department.
- >40 mg/dL = considered positive.
- >80 mg/dL = considered drunk driver.
- Toxic level
- Toxic level of ethanol = > 100 mg/dL
- Toxic level of methanol = > 20 mg/dL.
- Toxic level of Isopropanol = > 40 mg/dL
- lower limit of detection is 10 mg/dL.
- >80 mg/dL is considered positive for driving under the influence in most of the states.
- >300 to 400 mg/dL is considered fatal.
|Blood alcohol level
|100 to 200 mg/dL
Patient has emotional instability and there is a loss of critical judgment
|200 to 300 mg/dL
The patient is confused with impaired balance and disorientation.
|300 to 400 mg/dL
The patient is unable to walk or stand and is stuporous.
|More than 500 mg/dL
The 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 (%)
||Feels Soberness and calm
|0.05 to 0.1%
|0.1 to 0.2%
|0.2 to 0.3%
|0.3 to 0.4%
||Now is stuporous
||Goes into coma and death may occur
|Blood alcohol concentration g/dL
||Stage of alcoholic influence
|0.01 to 0.05
|0.03 to 0.12
|0.09 to 0.25
|0.18 to 0.30
|0.25 to 0.40
|0.35 to 0.50
|0.45 + (>0.45)
Possible References Used
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