EtG Hair Test: Definition, How it Works, and Accuracy
26 October, 2023
There are several methods to test for alcohol in the system. One of the methods is to detect ethyl glucuronide (EtG), a direct biomarker of ethanol. The EtG hair test can trace alcohol metabolites for several months after consumption. Thus, it can determine long-term alcohol use. The process works by collecting a few hair strands and testing them in a laboratory. It provides high accuracy as the hair is the most stable among other test samples.
Alcohol testing aims to determine if a person is intoxicated or impaired. Various methods can detect alcohol, such as breath, urine, saliva, and hair testing. Each type has different accuracy levels and detection windows. Hair alcohol testing is valuable for specific circumstances like the diagnosis of alcohol abuse. In this article, we will explore the hair test for ethyl glucuronide, how it works, and the accuracy and reliability of the results.
What is an EtG Hair Test
The EtG hair test is a type of drug test that detects the metabolites of ethanol in the hair sample. It determines if a person has consumed alcohol within a specific timeframe. It involves collecting a certain amount of hair, typically from the back of the head near the crown. The laboratory analysis then quantifies the amount of EtG in the sample.
Hair testing is commonly used in situations where alcohol use needs to be monitored. Such cases include probation, drink driving, child custody disputes, and workplace testing. Additionally, hair samples can trace drug or alcohol use for 90 days. This long detection window allows for the detection of alcohol abuse. It can determine the consumption patterns as well as periods of abstinence.
However, there are limitations to this test. EtG in hair can indicate chronic alcohol consumption but not measure the concentration levels. Therefore, healthcare providers often use hair testing with other methods, such as urine or blood tests, to get an accurate picture of the person’s alcohol consumption.
Benefits of the Test
- Hair follicle tests can detect alcohol over a longer period of time compared to other testing methods.
- The long detection window helps in the detection of alcohol abuse.
- It is a non-invasive way to test for alcohol. Obtaining the sample is easy and does not have privacy concerns, unlike urine tests.
- Hair tests can detect alcohol markers even in low amounts.
- It is valuable in monitoring abstinence in rehabilitation programs.
- It can be used with alcohol abuse screening tests like AUDIT questionnaires.
- EtG tests can identify the metabolites of ethanol and rule out possible external contaminants.
How an EtG Hair Test Works
The EtG hair tests start by collecting head hair and sending it to a laboratory for analysis. Body hair samples may also be used if head hair is not available. In the lab, the technician washes the sample of hair to remove any external contaminants that may be present on the surface. Testing facilities often use solid phase extraction (SPE) and liquid chromatography-tandem mass spectrometry.
After consumption, the body breaks down alcohol into various metabolites, including EtG. Traces of EtG deposit in the hair follicles and remain there as the hair grows. Thus, samples of hair can reveal the use of alcohol over time. The longer the hair strands, the longer its lookback period. This can help determine a person’s drinking history or possible alcohol abuse.
The process involves subjecting the samples to a series of chemical processes to extract EtG. The presence of minor ethanol metabolites indicates direct alcohol consumption. Laboratories also follow the established standards for the interpretation of ethanol concentrations in hair.
Who Can Be Tested
EtG testing can be conducted on anyone who needs to undergo screening for alcohol abuse. This includes people under probation and child custody cases. The court may mandate hair follicle alcohol tests if alcohol use is a factor. For example, it is part of the child custody proceedings, especially if the parents have alcohol abuse problems.
Healthcare providers also use this method to monitor alcohol abstinence. It can help determine if a patient follows the prescribed treatment for alcohol withdrawal. Additionally, employers may use this test to monitor their workers in high-risk jobs. This includes safety-sensitive positions like those involving transportation or operating machinery.
Accuracy of an EtG Hair Test
The EtG hair test is an accurate method of detecting direct markers of ethanol. It can identify trace amounts of alcohol in the hair strands even after a long time. In addition, hair specimens allow for multiple retests. Unlike blood or urine samples, which can degrade over time, hair is a stable matrix that can retain the presence of ethanol for an extended period.
The method also uses advanced techniques for accurate detection of alcohol consumption. Moreover, EtG tests have high specificity. It can rule out external contaminants, such as second-hand smoke, perfume, and medications containing alcohol. Additionally, laboratories use established abstinence thresholds for the interpretation of results. Therefore, it is reliable in legal proceedings and forensic context.
Individuals could not easily tamper with the sample to manipulate the results. Likewise, even if a person stops drinking for several days, the test can still show a positive test result due to its wide window of detection. Lastly, the test undergoes several stages of testing and confirmation to ensure the accuracy and validity of the result.
Factors that May Influence the Result
The accuracy of the test may vary due to several factors. EtG can undergo changes due to intrinsic factors like age and medical conditions. For example, elevated enzyme levels in comorbid illnesses may lead to false positives. Certain medications may also interfere with the results. The laboratory technician must take note of these factors before performing the test.
Furthermore, extreme cosmetic treatments alter the hair matrix, rendering the sample to be unsuitable for testing. For instance, bleach may affect the EtG levels in hair. Lastly, body hair has different growth rates than head hair, which may affect the quality of the sample.
EtG hair test is a reliable and accurate method of detecting alcohol use. It analyses the sample of hair using advanced laboratory techniques. Therefore, it provides extensive information about a person’s alcohol consumption history. The test is useful in various circumstances, such as rehabilitation programs, legal proceedings, and workplace monitoring. Individuals under probation or working in safety-sensitive roles often take this test. It is also valuable in determining if a person has alcohol abuse.
The sample collection is fast and simple. It requires a few strands of hair, typically from the scalp. It also does not require special preparation or fasting before testing. In addition, laboratories follow standards for interpreting the results. This helps minimise the possibility of false positives or negatives. However, individual factors may affect the accuracy of the test. Therefore, testing officers must consider these factors and other limitations when performing the test.