Diagnostic Tests for Alcoholism: Blood, Hair Follicle, and CDT
19 October, 2023
Diagnostic tests for alcoholism are vital to verify the identity of those who suffer from Alcohol Use Disorder (AUD). There are different methods of testing alcohol consumption, which include blood tests, hair follicle tests, and CDT tests. A blood test typically has a detection window of 6 to 12 hours. Meanwhile, hair follicle tests can trace alcohol use for up to 90 days. Lastly, a CDT test measures transferrin levels within two to four weeks before collection.
These tests are essential in providing evidence in legal proceedings and determining the alcohol intake history of an individual. Although blood tests are invasive, they also supply the most accurate results. Additionally, hair follicle tests are helpful because hair samples hold the substance use history of an individual. This article will present what blood, hair follicle, and CDT tests are and the corresponding procedures for these tests.
Diagnostic Tests for Alcoholism: Blood Test
An alcohol blood test is one of the reliable diagnostic tests for alcoholism. It is an intrusive test because it involves drawing blood from the person. However, it is also the most accurate test. Using the blood sample, a lab may use a Phosphatidylethanol (PEth) test to identify the level of ethanol in the bloodstream. This test only detects ethanol, making it less prone to false-positive results.
Generally, a blood test has a detection window of 6 to 12 hours after the last alcohol intake. However, it may vary depending on how the body metabolises the alcohol and the amount of alcohol consumed. Some factors that influence how the liver metabolises alcohol are age, body weight, medications taken, and overall health.
Furthermore, a PEth can trace ethanol biomarkers within two to four weeks after their last consumption. With this, healthcare professionals can determine if their previous alcohol assessment test is accurate. This is why this test is often used in legal proceedings. Courts require it from people with previous Driving Under the Influence (DUI) charges.
Procedures for a Blood Test
Medically trained professionals collect samples for blood tests. These are the steps:
- First, the administrator must ensure that the person has not consumed alcohol or other substances that may interfere with the results.
- Next, the collector draws the blood sample from the arm using a small needle. However, for a PEth test, they only need to prick the finger and get small amounts of blood.
- During the collection, the individual may feel a sting.
- Afterwards, the sample is placed into a test tube or vial.
- Lastly, the sample is transported to a laboratory for testing.
Diagnostic Tests for Alcoholism: Hair Follicle Test
Diagnostic tests for alcoholism also include the hair follicle test. It uses hair strands to check for the use of alcohol for up to 90 days before the test. It is a non-invasive procedure that typically uses head hair. This is because it is the fastest-growing and holds the most recent traces of drug use. However, if hair from the head is unavailable, body hair from the armpit and the leg suffice as alternatives.
An alcohol hair test detects ethyl glucuronide (EtG) markers. It is a metabolite present only after consuming alcohol. EtG readings show the amount of alcohol consumed by the person. This and its lengthy detection window make the hair follicle test ideal for tracking alcohol intake patterns.
However, there are limitations to the hair follicle test. Firstly, the colour and texture of the hair affect the amount of traces found. Secondly, it cannot detect alcohol intake from the past seven days due to the nature of hair growth. Lastly, damaged hair or chemical treatments affect the substance concentration found.
Procedure for a Hair Follicle Test
A collector cuts 100 to 200 strands of hair from the head to gather samples for a hair follicle test. Specimens are taken from different areas to avoid leaving a bald patch. The length of the hair should be at least 1.5 inches to cover 90 days of use. Afterwards, they take the samples to a lab for analysis.
From there, lab technicians wash the samples to remove external contaminants. They use the ELISA (enzyme-linked immunosorbent assay) testing technique to detect the traces of alcohol. However, if the results are positive, they use gas chromatography and mass spectrometry (GC/MS) methods to examine the specimen more.
Diagnostic Tests for Alcoholism: CDT Test
The Carbohydrate-Deficient Transferrin (CDT) test is one of the more accurate diagnostic tests for alcoholism. It is another form of blood test that detects the protein called transferrin. This protein increases when people drink large amounts of alcohol. It also goes down and returns to normal once the individual has stopped their alcohol intake for two weeks.
This test detects excessive alcohol consumption two to four weeks before the sample collection. Thus, it identifies those who suffer from alcohol misuse. Additionally, it detects if a person undergoing rehabilitation has relapsed. Those who drink four or more drinks daily for at least five days a week show high levels of CDT compared to those who drink moderately.
However, CDT tests also have limitations. For some people, alcohol consumption does not raise the CDT levels in their bloodstream. This can cause a false negative result. On the other hand, some factors cause false positives. Some individuals with liver conditions like cirrhosis and end-stage liver disease are examples of this.
Procedure for a CDT test
The procedure for a CDT test is invasive because the collector will need to draw blood from the person. To avoid contamination, the skin is cleaned with a disinfectant. Afterwards, the collector will collect blood from the arm. During this process, the person may feel a stinging sensation. Approximately ten cc of whole blood is drawn to get a sufficient sample.
In the lab, the technicians use electrophoresis to separate the proteins in the blood. The results of this test typically arrive after five days. However, in some cases, it may take up to two weeks.
Diagnostic tests for alcoholism help medical professionals identify the history and patterns of alcohol consumption of individuals. Excessive alcohol consumption brings many adverse effects to the individual and the community. Thus, it is vital to have early intervention for those suffering from AUD or who are at high risk for alcohol misuse. Furthermore, these results provide legal evidence for police to solidify their prior tests after an accident or roadside test.
The awareness of the individual to their risk levels for alcohol misuse may discourage alcohol consumption. This is beneficial because it prevents them from developing health conditions like cirrhosis or fatty liver disease. Moreover, it can help them become more aware of the symptoms of alcohol misuse. Some people may benefit from having a personal breathalyser. This can help them monitor and limit their alcohol intake. A BACtrack device from Breathalysers Australia uses sensors similar to police-grade tests.