QUESTION: Can one buy an at-home strep throat test device? I've heard you can, but I have no idea where. - E.V.

ANSWER: I know of no home test for strep throat germs. There are newer, faster office tests for strep identification. And there are the tests in which the germ is grown in laboratories.I'm not sure a home strep-germ tester would be really advantageous. For one thing, a negative result is not 100 percent reliable. You can get a negative result from a test, yet still have a strep infection.

Strep diagnosis, therefore, requires some detective work by the physician. He has to put together a puzzle, of which the test result is but one piece. He must observe the throat firsthand, check for lymph node enlargement, and note the patient's temperature and white blood-cell count. These factors help him establish strep infection and the need for antibiotic treatment.

To be honest, I wouldn't even try to do this for myself. I'd leave it to my doctor. I know you are thinking of the money savings possible in office visits and perhaps unneeded antibiotics if you could only determinme that a sore throat is from viral as opposed to strep germ causes. (Not much you can do to treat a virus sore throat.) But are you willing to risk unreliable diagnosis when the danger from not treating strep throat promptly is so great? I am thinking of possible rheumatic fever and its consequences from untreated strep infection.

No matter, if you ever find that there is, indeed, an at-home strep germ detector, let me know about it.

QUESTION: How many calories in an average bottle of beer as opposed to a jigger of whiskey? Incidentally, is teenage alcoholism as widespread as they say it is? - Mrs. L.J.

ANSWER: An average 12-ounce bottle of beer has about 150 calories. A jigger of whiskey has about 124 calories. Teenage alcoholism is becoming a national tragedy. I have heard figures as high as 500,000 for those under 19 who meet the description of an alcoholic. The matter of alcohol effects, physical and social, is discussed in the new alcohol report, which I'm sending on to you. Others may order by writing: Dr. Donohue/No.41, Box 830, Gibbstown, NJ 08027-9909, enclosing a long, double-stamped, self-addressed envelope and $2.

QUESTION: Could you please tell me where I can get a medical dictionary? I would like to order one if possible. I want to know what the medical terms mean on my doctors' reports. - M.T.

ANSWER: There are many fine medical dictionaries. Dorland's is an example of one. It's published by W.B. Saunders Co. of Philadelphia. But before you go ordering such a text, why don't you visit your library? Perhaps you will find a condensed volume that would suit your needs just as well as one of the professional versions.

QUESTION: Please tell me in lay language, if possible, just what an IVP test is all about. - Mrs. N.

ANSWER: The initials are for intravenous pyelogram. "Pyelo" refers to kidney, the organ being viewed. Intravenous means that a contrast material (dye) is injected into a vein. In the kidneys, it brightens and darkens various tissues, providing a setting for subsequent clear X-ray pictures. It's safe, effective and requires no hospital stay.

Dr. Donohue welcomes reader mail but regrets that, due to the tremendous volume received daily, he is unable to answer individual letters. Readers' questions are incorporated in his column whenever possible.