Avoid BLOOD Test after Drinking Alcohol last night - Healthians

Avoid Blood Test After Consuming Alcohol Last Night

Contributed by-Dr. Pooja Chaudhary

Can I drink alcohol the night before a blood test?

This one question perplexes many minds. Though we all want to adhere to what our doctor advises us but when the question of alcohol arises, many want to escape regular health screening for the love of their drinks. This, in the long run, can have detrimental consequences.

Blood tests check the blood for abnormalities. These tests may seem very structured, but they are very easy to tilt. This mostly depends on the type of blood test a person is going to have. Most of the times a patient can eat and drink normally before the tests, whereas there are cases when you will be instructed not to eat or drink before the test. Alcohol is one of these restrictions.

Patients are advised to avoid alcohol intake a night before any medical test or procedure. Those who have recently already consumed alcohol prior to a blood test are advised to discuss the matter with their physician to determine if the test should be postponed.

Alcoholic beverages contain the psychoactive substance “ethanol,” which is known to temporarily improve mood, increase self-confidence, decrease anxiety, and promote socialization, so they must be avoided before any blood test as ethanol has the power to tilt blood test results.


Alcohol has a noticeable effect on the body, even when consumed in small amounts. Our body continues to break down alcohol at a steady rate after drinking. Trace amounts of alcohol may remain in the blood several days also after its consumption. Alcohol is metabolized at a relatively predictable rate. Most of the people can expect blood alcohol concentrations (BAC) to drop at a rate of 0.015 per hour.  This means that following last alcoholic drink of the night, the alcohol present in the body is being metabolized and eliminated at a rate of 0.015.

On an average to flush the impact of alcohol, the human body needs anything between 7 to 10 hours. This is totally dependent on the quantity of alcohol consumed. The thumb rule is the more you drink, the longer you should expect it to take for alcohol to clear from your body.


Patients are advised to abstain from drinking alcohol before fasting blood test as it may affect the blood results, causing irregular enzyme levels. Blood tests specifically prohibiting alcohol consumption prior to the administration include the triglyceride test and the gamma glutamyl transferase (GGT) test. It will lead to an elevated level of LFT’s (Liver Function Tests).

Those who have recently consumed alcohol prior to a blood test are advised to discuss the matter with their physician to determine if the test should be postponed. Each blood test is independent, so it is important to ask the doctor if you should fast before the test or take any other precaution (many tests require a patient to avoid a certain type of foods even 5-7 days before a test is conducted). So, fasting may be important because what you eat and drink may change test results.

(Also Read: Are my lab results affected by when and what I ate last night?)

Blood tests also can help find potential problems at an initial stage, when treatments or lifestyle changes may work best. Hence, if your doctor has advised you not to consume alcohol before the test, then the instructions should not be ignored.

Remember, love your drink but love yourself more!


Take Care Of Your Health

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  • GGT Test

    Thanks so much for sharing all of this health information and your through research. Glutamyl Transferase Test is used to evaluate the functioning of liver, bile duct and pancreas. It is widely used for the diagnosis of any kind of liver damage. Screening of this enzyme, along with some other (Aspartate aminotransferase (AST) and alanine aminotransferase (ALT), provides information about the status of liver function.

  • My daughter had a lot to drink on Sunday night and felt bad all last week. She went to an urgent care on Friday and had labs drawn. She received a call today that her AST was 175 norm (0-40) and ALT 531 (0-32). She does not normally drink to excess or frequently. She is 27 yo. Would the alcohol still be in her system enough after 5 day to result in such an elevated level? They are doing an US of the liver in the morning.

  • Susie

    I had 2 beers and a 2 glasses of wine. I went in for a blood test the next day. Now, my white cell blood counts are low. Could this be a result of the beer and wine?

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