ASK THE DOCTOR

by Wesley W. Wilson, MD

NOTE: If you have any questions for "Ask the Doctor," please send them to the VOICE editorial office. The only questions Dr. Wilson will be able to answer are the ones used in this column.

Wesley Wilson, MD is an Internal Medicine practitioner at the Western Montana Clinic in Missoula, Montana. Dr. Wilson was diagnosed with type I diabetes in 1956, during his second year of medical school.

Q: I am working hard to control my diabetes and check blood sugars before each meal and at bedtime. I also occasionally check between meals or when I suspect my blood sugar is "not right." My fingers are sore from all the blood tests. Can I use any other spot?

A: Your attention to detail is great. Careful control does require frequent blood sugar testing, and for most persons with diabetes, that tends to be the most troublesome part of managing their illness. You brought up a point that is important to me personally, since I like to know where my blood sugar is, but don't like to stick my fingers, nor do I like having holes in my protective skin over my fingers, particularly when I see patients in my office who have hepatitis or other infectious problems.

There are more nerve endings in the fingertips than almost any other part of the body, so blood sugar sampling from fingertips, even with the new super-sharp lancets, sometimes causes discomfort.

Because I wish to have my fingertip skin left intact but test frequently, I did a study several years ago in which I checked a blood sugar from my finger, another from the area just above my kneecap, and another venous blood sample taken by the laboratory and run on their precise equipment to check blood sugars. All the tests were done within five minutes. Then I compared the three test group results after I had done the three tests on 40 separate occasions.

The blood sugar samples from the finger were dropped onto the test strip. The blood sample from above the knee required squeezing the skin to get a large drop of blood on the surface of the skin, and then the test device had to be turned upside down and placed on top of the drop of blood.

The three separate tests all matched very closely. The blood sugar from the knee was as accurate as the blood sugar from the fingertips, and they all agreed very closely with venous blood samples done in the laboratory.

I have used this method with a variety of glucose monitors, including Glucometer, Accu-Chek Advantage, and Medisense; and they all seem to work reasonably well, though some are more convenient than others. Some glucose meters require the blood to be applied to a strip already inserted, making it very difficult to get a drop of blood on the test area.

The point is, it is important to check sugars frequently, and the blood can be obtained from spots other than the finger. The important requirements for testing from above the kneecap are: (1) your need to get a large enough sample of blood, (2) you need a meter whose test strips are such that the blood can be non-traditionally applied, and (3) squeezing the punctured skin to force the drop of blood out does not affect test accuracy.