For most accurate BP readings, one must follow procedure

DEAR DR. ROACH >> I monitor my blood pressure at home as part of my regular wellness routine. The instructions for the BP monitor say to sit upright, keep my feet on the floor and to not place the cuff over clothing. In addition, directions indicate that the cuff should be placed at the level of the heart.

I have rarely been in a doctor’s office where the staff taking my blood pressure follows this procedure. I am almost always sitting on the exam table with my legs dangling, and the cuff is always placed over my clothing. When I have raised this with the staff taking the reading, my comments usually are brushed off. My BP is usually a little high when I am in a doctor’s office (compared with my home readings), and I understand that this is not uncommon. How can a doctor really identify that I might have a blood pressure problem if the basic procedure isn’t properly administered for the only monitoring of BP he or she does?

— M.D.W.

DEAR READER >> You are right that your blood pressure was not measured correctly. Worse, the error in the blood pressure measurement could adversely affect your treatment, potentially causing you to be over- or undertreated. Worse still, when you tried to make sure your blood pressure was measured correctly, you weren’t listened to.

When it really matters — for example, when taking care of a person with high blood pressure — the blood pressure should be measured very carefully. The home measurements actually may be more useful, as there are more results, which minimizes random error, and they are taken in the situation where people live, not the artificial situation of a physician’s office. However, the doctor should make sure the device is accurate before relying on the readings.

Finally, there is increasing evidence that measuring the blood pressure many times over 24 hours may be useful, especially in cases of suspected “white coat” hypertension.

Contact Dr. Roach at ToYourGoodHealth@med. cornell.edu.