Alcohol Tests: Uses, Types, Results, And Implications

According to the “Global Status Report on Alcohol and Health” by the WHO, alcohol abuse and alcoholism are worldwide problems. It causes hundreds of thousands of deaths every year. It is a precursor to violence, injury, and several diseases.

Furthermore, the negative impacts of alcohol spread throughout a family, community, country, and beyond.

Alcohol consumption by the general public is increasing rapidly. Consequently, there is a growing demand for more drug and alcohol testing, screening, and detection.

Testing for alcohol through clinically proven methods verifies the use of alcohol over some time by an individual.

When do you need an alcohol test?

One may have to undergo an alcohol test for a variety of reasons, such as:

  • Pre-employment screening
  • During the probation period for alcohol-related crimes
  • Mandatory workplace screening programs for alcohol use
  • For granting a visitation permit or custody of children
  • Identifying drivers suspected of drinking and driving
  • For de-addiction treatment and rehabilitation
  • As part of the police investigation procedure in criminal cases

Levels of alcohol consumption

Ethanol, or ethyl alcohol, is the only alcohol suitable for consumption without harming yourself. The percentage of alcohol in the system is the amount of ethanol consumed.

  • Abstinence: No consumption of alcohol
  • Occasional Drinking: If you consume less than 40 grams of pure ethanol a day, it is considered occasional drinking.
  • Alcohol Abuse: Excessive use of alcohol is defined as consuming more than 40 grams of pure ethanol daily. Half a bottle of wine has over 40 grams of ethanol.
  • Alcohol Poisoning: large amounts of liquor in the body.

Even if a person drinks less than the legal limit, their reaction time can still be affected.

Types of testing

We are all familiar with police officers testing drivers with breathalyzers for alcohol. An alcohol screen test measures the amount of alcohol in your system.

For assessing current intoxication or a history of prior alcohol and drug consumption, a variety of specimens and methods can be used. Common specimen tests include:

  • Breath
  • Blood
  • Sweat
  • Urine
  • Hair testing
  • Fingernail
  • Saliva
  • Breast milk

Testing window

Drug tests may show up for alcohol from 10 hours to 90 days, depending on your metabolism and the test method. Here are the usual detection period for different tests:

  • Breath alcohol (BAC): up to 24 hours.
  • Blood indirect (CDT, LFT, FBC): 30 days
  • Blood direct (PEth): 30 days
  • Fingernail: 3-6 months
  • Head hair: 0-3 or 0-6 months
  • Body hair (chest, arm): 4–8 months
  • Body hair (pubic): 4–8 months
  • Saliva: 24 hours
  • Breast milk:: 30 days
  • Sweat: 80 hours

What do various test results mean?  

It is possible to assess an individual’s drinking habits through alcohol tests. According to the level of alcohol content in the specimens, here are some of the indications:

  • Breath (remote alcohol monitoring): social drinking, alcohol abuse, abstinence
  • Head hair: social drinking, alcohol abuse, abstinence
  • Body hair (chest, arm)—a result of social drinking or alcohol abuse
  • Body hair (pubic)—abstinence
  • Fingernails: alcohol abuse, social drinking
  • Urine: social drinking, alcohol abuse
  • Saliva: Social drinking, alcohol abuse
  • Blood direct (PEth): social drinking, alcohol abuse, abstinence within a week
  • Blood indirect (CDT, LFT, FBC)—alcohol abuse or abstinence with a limitation of 44–85% accuracy

Common tests for alcohol detection

The most common alcohol testing methods are blood, breath, and saliva. There are other specimens, like hair, nails, sweat, and breast milk. A person’s drinking habits or abstinence from alcohol can be diagnosed with these tests. Below are brief notes on each type of alcohol testing.

Hair testing

Testing head-hair samples is an accurate way to verify the alcohol consumption habits of an individual for up to 3 to 6 months.

Hair testing is mainly of two types, such as:

The testing window for hair testing depends on the length of the hair. A hair length of at least 3 cm offers a three-month detection window, and a hair length of 6 cm provides a 6-month detection window. However, testing hairs below 3 cm in length reduces the alcohol detection period to below three months.

Always combine EtG hair testing with blood tests to get more accurate results. Similarly, FAEE testing is suitable for chemically treated hair, like bleached or dyed hair.

Blood alcohol test

Blood alcohol level testing is a proven clinical option to detect potential alcohol abuse by an individual.

The blood alcohol content (BAC) legal limit is 0.03% or 30 µl alcohol in 100 ml blood.

Alcohol in your blood sample can be detected for up to 36 hours using the EtG test. But the most accurate results of alcohol in the blood are detectable between 6 and 12 hours after the last drink.

Both indirect and direct biomarkers may be used in various types of alcohol blood tests, such as:

  • Full Blood Count (Mean Conspicuous Volume – MCV) – indirect
  • Liver Function Test (LFT)—Indirect
  • Phosphatidyl Ethanol (PEth)—Direct
  • Carbohydrate-deficient Transferrin (CDT)—Indirect

Fingernail testing

Fingernail testing is a suitable alternative to hair testing.

EtG (ethyl glucuronide) works well in nail tests.

The metabolites of drugs and alcohol travel to the blood vessels under the nail. They are trapped within the keratin fibers.

Nails can hold more metabolites than hair because of their thickness and volume.

It is possible to trace the elements of alcohol in nails for 3–6 months. Growth, length, and frequency of trimming the nails influence the detention period.

Unfortunately, there needs to be more clarity on which segments of the nails are relevant to such tests. There needs to be more studies and clarity on nail testing.

Urine testing

One of the common tests for alcohol in your system is urine testing. The detection period varies according to the testing tools.

Ethanol urine testing

Ethanol is the alcohol content of alcohol. The liver breaks down ethanol and dispels the metabolized ethanol through urine, sweat, and breath.

Ethanol urine tests can effectively detect the presence of ethanol in the urine.

Tests can easily detect ethanol in urine between 2 and 12 hours after having the last shot of alcohol.

An ethanol urine test can go wrong for some reasons, such as::

  • If your urine is left out at room temperature,
  • Urinary tract infections
  • Diabetes affects
  • Yeast

EtG urine test

Ethyl glucuronide, or EtG, is generated when the liver breaks down alcohol. EtG stays in the body for a longer time than ethanol.

The detection window for EtG is from 8 hours to 80 hours after the last drink.

EtG tests do not indicate the timing of alcohol; they are not useful in examining cases such as DUI and DWI.

Breath test

The alcohol breath test is the most common type of alcohol test. It is a very handy testing method used by traffic police to detect DUI.

You can find different types of breath tests for alcohol detection. All of them measure the amount of alcohol in your breath. They all indicate the amount of alcohol present in your bloodstream.

A breath test works best 15 minutes after drinking or one minute after smoking.

A breathalyzer detects the level of blood alcohol concentration. A breathalyzer test can be positive for up to 12 hours after the last drink.

Saliva test

After drinking alcohol for 1 to 24 hours, the EtG test can detect alcohol in saliva. On the weaker side, this test does not indicate the level of alcohol in the body.

Breast milk test

Drinking is not an appropriate option for nursing mothers. After a drink, breastfeeding mothers should wait at least two hours before nursing or pumping. Pumping and dumping don’t immediately eliminate the alcohol in your breast milk.

Alcohol levels peak in milk from 30 to 60 minutes after a drink. Breast milk contains alcohol for 2 to 12 hours.

The final thought 

Different alcoholic drinks like wine, beer, and liquor break down differently in each person’s body. Therefore, the detection period for each type of drink and other biological factors influence the outcome of alcohol tests.

The most commonly used alcohol tests are breath and urine tests. However, hair or fingernail tests offer a longer detection window for alcohol testing. Blood and saliva tests have a shorter detection period, less than 48 hours at most.

Recommended reading list:

Article source:

  • Dahl H, Voltaire Carlsson A, Hillgren K, Helander A. Urinary ethyl glucuronide and ethyl sulfate testing for detection of recent drinking in an outpatient treatment program for alcohol and drug dependence. Alcohol Alcohol. 2011;46(3):278-82. doi:10.1093/alcalc/agr009
  • Global status report on alcohol and health
  • Jallow P, O’Malley SS. Clinical (non-forensic) application of ethyl glucuronide measurement: Are we ready? Alcoholism, Clinical and Experimental Research. 2010;34(6):968-975.
  • The BMJ. “Alcohol in the body.” Published January 2005. Accessed March 28, 2019.
  • Shukla L, Sharma P, Ganesha S, et al. Value of Ethyl Glucuronide and Ethyl Sulfate in Serum as Biomarkers of Alcohol Consumption. Indian Journal of Psychological Medicine. 2017;39(4):481-487.
  • “Ethyl glucuronide in hair and fingernails as a long-term alcohol biomarker.” Published December 2013. Accessed March 28, 2019.