"They can see it in your blood"
(Older adult describing how doctors know if a person has an alcohol problem)
Some older adults are first advised to cut down their drinking or to stop drinking after certain blood tests have been done to check their liver function and general state of health.
The National Institute on Alcohol Abuse and Alcoholism (NIAAA) in "Alcohol Alert # 56" ("Screening for Alcohol Problems—An Update") talks about screening for alcohol dependence (1).
There is no specific laboratory test for alcohol problems, but some tests can suggest the need for follow up to determine if a problem exists.
Researchers point out that current blood screening tests are not very sensitive (they miss most people with alcohol problems) but are fairly specific (if a person tests positive, she or he probably has an alcohol use problem).
Liver function tests can identify chronic ingestion of alcohol, but not always. Some older and younger adults with severe advanced liver disease will have normal or nearly normal enzyme levels. Many people are unaware that the incidence of liver cirrhosis among individuals who have alcohol problems is only 10-30%. (2)
Asking the older person and those close to them specific questions about drinking in a non-judgmental way is probably the best way to find diagnostic evidence of an alcohol use problem.
Commonly Used Tests
NIAAA explains some of the blood tests commonly used, other than just looking at people's blood alcohol content:
A. Gamma-glutamyl transferase (GGT) is an enzyme from the liver that can be found in excess in the blood of heavy drinkers. Chronic drinking of 4 or more drinks per day for 4 to 8 weeks significantly raises levels of the blood protein. If a person stops drinking for 4-5 weeks, then the levels of GGT decrease to normal levels. The test is seen as having low sensitivity and moderate specificity for alcohol use.
B. Increased red blood cell size (Mean Cell Volume, or MCV): A good indicator of someone having recently ingested alcohol is the "mean corpuscular volume" of the red blood cells. If the person has recently had alcohol to drink, the cells become large, so the MCV is high, usually 100 or more. This happens as a result of several factors -- direct effect on the red blood cell membrane, vitamin deficiencies i.e. folate or direct effect on the bone marrow.
The increased red blood cell size is due to bone marrow toxicity from alcohol use.
These two tests (GGT& MCV) are commonly elevated in older adults, whether or not there is a real alcohol problem. (3)
MCV tests show the greatest specificity (100%) where the person is consuming >100 g alcohol/day (4), which for most older adults would be very high levels of drinking.
There are other tests that suggest alcohol use. For example,
Obvious liver dysfunction tests that may point to alcohol abuse include
* A blood alcohol level that is > 100 mg/dL (> 21.7 mmol/L) without signs of intoxication is a good indication of tolerance to alcohol and usually signifies the presence of an alcohol problem. A blood alcohol level test will be good only in looking at recent alcohol use, as 1 - 2 days abstinence will clear the system of alcohol.
References and Resources
(1) NIAAA Alcohol Alert # 56" ("Screening for Alcohol Problems—An Update") www.niaaa.nih.gov/publications/aa56.htm
(2) F. Wong and L. Blendis, First Principles of Gastroenterology, Chapter 14, http://gastroresource.com/GITextbook/En/Chapter14/14-6.htm
(3) Adams, W. Chapter 37. Substance Abuse and Dependence. Merck Manual of Geriatrics. www.merck.com/pubs/mm_geriatrics/sec4/ch37.htm
(4) Viitala, K, Carbohydrate-deficient transferrin (CDT) and serum antibodies against acetaldehyde adducts as markers of alcohol abuse. Academic Dissertation, presented November 27, 1998, Faculty of Medicine, University of Oulu. http://herkules.oulu.fi/isbn9514251075/
(5) Oslin, D. W. & Holden, R. (2002) "Recognition and Assessment of Alcohol and Drug Dependence in the Elderly." Gurnack, et al. (eds.) Treating Alcohol and Drug Abuse in the Elderly. Springer Publishing, 11-31.
Page last updated 31/10/2004;
Prepared by Charmaine Spencer