DEAR DR. DONOHUE: I have diabetes and have my blood sugar tested quarterly. I had been in the habit of testing my blood with a device provided to me by my doctor. I detected a difference in the reading I got and the one the lab got. I called and was told that the home device was accurate within 20 percent of the lab reading. I consider that to be similar to Amtrak claiming it is on time 100 percent because it considers anything within 12 hours of the posted time to be on time. I have not used the meter since then. — J.R.

ANSWER: Glucometers, small devices that provide an instant reading of blood sugar so that patients can monitor what their level is at home, have been a godsend for diabetics. They’ve been in use for 30 years or more. Diabetics have used them to make changes in their diet and dose of medication.

The Food and Drug Administration requires that all glucometers give a reading that is, at maximum, within 20 percent of lab reading. That doesn’t mean that every reading is going to be off by 20 percent. Most readings are at only a slight variance from the lab reading, if at any variance. The results are accurate enough to make good decisions on adjusting the dose of medicine and modifying the diet.

If you want to check the validity of your meter, you can test it using control solutions, liquids with a known glucose (sugar) content. The manufacturers of meters provide control solutions that can be bought. You might find them in retail establishments that sell such meters.

Retrieve your meter from the junk, and start testing yourself again.

DEAR DR. DONOHUE: You discussed the importance of getting immediate attention for a person suspected of having a stroke. I have some questions.

In addition to calling 911, should a suspected stroke victim be given aspirin? You say 80 percent of strokes are due to clots, so aspirin seems appropriate. Do emergency response units give clot-dissolving drugs, or are they not given until the patient arrives at the emergency room? — R.H.

ANSWER: Most strokes are ischemic strokes — strokes due to obstruction of blood because of a clot in a brain artery. Twenty percent, however, are due to bleeding in the brain. It’s difficult to differentiate which kind of stroke a person has without a brain scan. Giving aspirin to a person who has had a brain bleed would almost seal the person’s death. Clot-busting drugs are given in the ER. They don’t prevent the clot from growing bigger, as aspirin does. They actually dissolve the clot. That’s why it is so urgent to get a person to the ER as soon as possible. There’s about a three-hour window for saving brain tissue with those clot-dissolving drugs.

The booklet on strokes goes into their types and treatments. Readers can order a copy by writing: Dr. Donohue — No. 902, Box 536475, Orlando, FL 32853-6475. Enclose a check or money order (no cash) for $4.75 U.S./$6 Can. with the recipient’s printed name and address. Please allow four weeks for delivery.

DEAR DR. DONOHUE: I was recently diagnosed with prostate cancer and am under active surveillance.

I know that testosterone can be bad for my condition. Does lovemaking cause my body to produce testosterone? If so, should I avoid it? — D.L.

ANSWER: Lovemaking does not increase testosterone production. It is not off-limits to a man with prostate cancer.

Another question frequently asked is the possibility of transferring prostate cancer to one’s partner. The answer to that also is no.

Dr. Donohue regrets that he is unable to answer individual letters, but he will incorporate them in his column whenever possible. Readers may write him or request an order form of available health newsletters at P.O. Box 536475, Orlando, FL 32853-6475. Readers may also order health newsletters from www.rbmamall.com.

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