Some criminal offenders are given probation instead of a prison term. In this case probation officers have to test them for various illegal substances as well as alcohol while they serve their probation. They usually test for cocaine, phencyclidine, opiates, methamphetamines, marijuana and alcohol. For the first five the most common way of detection is hair follicle screening, which can detect if the mentioned substances have been taken during the last 90 days. The test for alcohol can differ in different countries and also in different areas, however the most common test is the breathalyser test, where the person in question has to blow into the tester which detects the person's blood alcohol content. It is the most commonly used method because it is simple and quick to use and is usually, however it only detects alcohol that is currently in the system. For this reason some probation officers use other methods of detection such as the 10 panel drug test which is a urine test that can detect all of the illegal substances probation officers would be looking for. Another widely used alternative is the EtG (Ethyl Glucuronide) test that tests the person's urine for the by-product of ethanol, however it has been criticised lately because some say that it is too sensitive and it can be difficult to distinguish between low level alcohol consumption and household items such as personal hygiene products. A cheaper version of the EtG test is the EtOH test that looks for ethanol in the person's urine, however this has also been criticised for the same reason as the EtG test was. In conclusion although some alternatives are used, the most common alcohol test that probation officers use is the breathalyser test.
