Identification and diagnosis of alcoholism

Multiple tools are available to those wishing to conduct screening for alcoholism. Identification of alcoholism may be difficult because there is no detectable physiologic difference between a person who drinks frequently and a person with the condition. Identification involves an objective assessment regarding the damage that imbibing alcohol does to the drinker's life compared to the subjective benefits the drinker perceives from consuming alcohol. While there are many cases where an alcoholic's life has been significantly and obviously damaged, there are always borderline cases that can be difficult to classify.
Addiction Medicine specialists have extensive training with respect to diagnosing and treating patients with alcoholism.

Screening
Several tools may be used to detect a loss of control of alcohol use. These tools are mostly self reports in questionnaire form. Another common theme is a score or tally that sums up the general severity of alcohol use.
The CAGE questionnaire, named for its four questions, is one such example that may be used to screen patients quickly in a doctor's office.
Two "yes" responses indicate that the respondent should be investigated further. The questionnaire asks the following questions:
Have you ever felt you needed to Cut down on your drinking?
Have people Annoyed you by criticizing your drinking?
Have you ever felt Guilty about drinking?
Have you ever felt you needed a drink first thing in the morning (Eye-opener) to steady your nerves or to get rid of a hangover?
The CAGE questionnaire, among others, has been extensively validated for use in identifying alcoholism. It is not valid for diagnosis of other substance use disorders, although somewhat modified versions of the CAGE are frequently implemented for such a purpose.
The Alcohol Dependence Data Questionnaire is a more sensitive diagnostic test than the CAGE test. It helps distinguish a diagnosis of alcohol dependence from one of heavy alcohol use.
The Michigan Alcohol Screening Test (MAST) is a screening tool for alcoholism widely used by courts to determine the appropriate sentencing for people convicted of alcohol-related offenses, driving under the influence being the most common.
The Alcohol Use Disorders Identification Test (AUDIT) is a screening questionnaire developed by the World Health Organization. This test is unique in that it has been validated in six countries and is used internationally. Like the CAGE questionnaire, it uses a simple set of questions - a high score earning a deeper investigation.
The Paddington Alcohol Test (PAT) was designed to screen for alcohol related problems amongst those attending Accident and Emergency departments. It concords well with the AUDIT questionnaire but is administered in a fifth of the time.
A number of free websites provide anonymous self-screening for harmful or hazardous alcohol use, including AlcoholScreening.org and this online version of AUDIT.

Genetic predisposition testing
Psychiatric geneticists John I. Nurnberger, Jr., and Laura Jean Bierut indicate that alcoholism does not have a single cause—including genetic—but that genes do play an important role "by affecting processes in the body and brain that interact with one another and with an individual's life experiences to produce protection or susceptibility." They also report that less than a dozen alcoholism-related genes have been identified, but that more likely await discovery.
At least one genetic test exists for an allele that is correlated to alcoholism and opiate addiction. Human dopamine receptor genes have a detectable variation referred to as the DRD2 TaqI polymorphism. Those who possess the A1 allele (variation) of this polymorphism have a small but significant tendency towards addiction to opiates and endorphin releasing drugs like alcohol.Although this allele is slightly more common in alcoholics and opiate addicts, it is not by itself an adequate predictor of alcoholism, and some researchers argue that evidence for DRD2 is contradictory.
Some writers posit that alcohol was discovered to be a replacement for polluted drinking water in early urban societies. In these conditions, alcohol's antibacterial properties offset its health risk, and the slow death of cirrhosis of the liver was preferred to an early death from waterborne disease. This caused a selection pressure on the genes of humans who had abandoned the hunter-gatherer lifestyle towards people with genes which were not prone to over consumption and drunkenness. Over generations, the descendants of these first farmers and urban dwellers became dominated by individuals who could drink more beer more often. This theory explains why some groups who continued a predominately hunter-gatherer culture, such as Native Americans or Australian Aborigines, have such high rates of alcoholism today.

DSM diagnosis
The DSM-IV diagnosis of alcohol dependence represents one approach to the definition of alcoholism. In part this is to assist in the development of research protocols in which findings can be compared with one another. According to the DSM-IV, an alcohol dependence diagnosis is:
...maladaptive alcohol use with clinically significant impairment as manifested by at least three of the following within any one-year period: tolerance; withdrawal; taken in greater amounts or over longer time course than intended; desire or unsuccessful attempts to cut down or control use; great deal of time spent obtaining, using, or recovering from use; social, occupational, or recreational activities given up or reduced; continued use despite knowledge of physical or psychological sequelae.

Urine and blood tests
There are reliable tests for the actual use of alcohol, one common test being that of blood alcohol content (BAC). These tests do not differentiate alcoholics from non-alcoholics; however, long-term heavy drinking does have a few recognizable effects on the body, including:
Macrocytosis (enlarged MCV)1
Elevated GGT2
Moderate elevation of AST and ALT and an AST:ALT ratio of 2:1.
High carbohydrate deficient transferrin (CDT)