Q. My husband has had a problem with alcohol for some time now, but it wasn't until his doctor did some tests that we all learned there really was a problem. How can a doctor detect alcoholism in his or her patients?

A. Alcoholism makes you think you don't have a drinking problem. So discovering you have one can sometimes be very difficult. However, there are some clues your doctor can use to suspect you have a problem with alcohol use.

Two blood tests in particular have proved helpful in identifying potential problem drinkers. One is the MCV, or mean corpuscular volume, a measure of the average size of red blood cells. This test shows up on a complete blood count (CBC) and reflects alcohol-induced changes in the thin membrane holding the red cell together. Chronic alcohol abuse causes red cells to swell.

The other is the GGT (gamma glutamyl transferase), an enzyme that indicates alcohol-induced liver damage. Other liver enzyme levels that go up with short-term or long-term alcohol abuse include the SGOT (also known as AST) and SGPT (also known as ALT).

Several other changes in blood tests that excessive alcohol use commonly brings about are: 1) a rise in the uric acid level, perhaps making a doctor wrongly suspect gout; 2) an increase in blood fats, namely the triglycerides and HDL cholesterol; 3) a fall in the blood count, causing anemia; 4) a drop in the blood sugar level, and 5) the presence of measurable levels of alcohol itself. In particular, a blood alcohol level above the legally intoxicated range, without making someone seem intoxicated, is fairly conclusive evidence of excessive long-term alcohol use.

Let me emphasize, however, that these tests can't "diagnose" alcoholism. For one thing, many other conditions can also make these tests abnormal. For another, diagnosing a problem with drinking requires looking at the whole picture and seeing a pattern of alcohol interfering with one's life.

Other clues to unsuspected alcoholism include a long list of physical signs and symptoms. Although other conditions can cause these symptoms, they are typical of excessive alcohol use:

Emotional distress, such as anxiety, depression, irritability, memory problems, difficulty sleeping.

Fluctuating levels of blood pressure.

Abdominal pain, especially after a binge, caused by stomach irritation (gastritis) or severe abdominal pain caused by inflammation of the pancreas (pancreatitis).

Enlargement of the liver, a swelling brought on by alcohol- induced fatty deposits.

Various changes in the skin, including reddened palms, tiny "spider" arteries (telangiectasias) and dilation of the veins on the abdomen.

Having a blackout or seizure, or nerve problems resulting in numbness, tingling or burning, especially in the hands or feet.

A long history of accidents or trauma, such as car accidents, fractures, head injuries, fights or falls, even if there seems to be a reasonable explanation for them.

In short, alcohol may be at the root of almost any unexplained symptom. In many cases, even if the person is aware he's drinking too much, he may not tie his symptoms together with his drinking.

A final aid for physicians to discover a hidden drinking problem is the use of questionnaires like the Michigan Alcohol Screening Test (MAST) or the CAGE questionnaire, a simple four-question screen:

Have you ever felt you ought to cut down on your drinking?

Have people annoyed you by criticizing your drinking?

Have you ever felt bad or guilty about your drinking?

Have you ever had a drink first thing in the morning to steady your nerves or get rid of a hangover (eye-opener)?

"Yes" answers to two or more questions strongly suggest a problem with alcohol and the need for further evaluation.

Jay Siwek, a family physician from Georgetown University, practices at the Fort Lincoln Family Medicine Center and Providence Hospital in Northeast Washington.

Send questions to Consultation, Health Section, The Washington Post, 1150 15th St. NW, Washington, D.C. 20071. Questions cannot be answered individually.