Home measurement with an accurate machine can be very worthwhile, it can give you more control over your blood pressure and be reassuring. Many patients also find that their readings are lower at home than in the surgery.
In general an upper arm monitor will give you a more accurate reading and all of the research studies on blood pressure have been done with measurements from the upper arm. The first wrist monitor to be validated as accurate by the British Hypertension Society has recently been added to their list (see below). If you want to use a wrist monitor, it is vital that you follow the instructions for use very carefully, as the cuff around the wrist needs to placed exactly at the level of the heart to give an accurate reading. Even then, a special computer chip has to change the reading because blood pressure is different at the wrist compared to the upper arm.
Click on the following link to view blood pressure machines that are of a good quality (validated by the British hypertension society):
Wrist devices are subject to errors that are not presently evaluated in the available validation protocols. The most important source of error with wrist devices is the position of the arm in relation to the heart. A wrist device may fulfil the accuracy criteria of a validation protocol when strict attention is paid to having the wrist at heart level but in home use this may not happen and as a consequence the measurements can become inaccurate. For this reason validated upper arm devices are recommended in preference to wrist devices.
We recommend that you purchase a home Blood Pressure monitor that is validated by the British hypertension society.
To view wrist devices that are acceptable view: www.bhsoc.org/bp_monitors
Non-urgent advice: How often should I be doing readings?
For patient with no known blood pressure problem, you can check your readings each day for 1 week or so; please make a record each reading, and then work out the average of each reading.
For patients with known blood pressure issues, or who are on tablets for high blood pressure, fall into two groups.
Firstly, there are those patients whose blood pressure is high and are checking their blood pressure – about once a week is fine.
Secondly, there are those patients who are known to have high blood pressure for which they are receiving treatment – these patients will want to monitor their blood pressure occasionally.
Patients with high blood pressure will be interested to know that readings at home can be much lower that at the surgery; this is called “white coat hypertension”; in fact, the nurse will add 10/5 to your home readings to get an equivalent surgery reading upon which the targets are based.
Please ask the nurse, next time you are in, what is your target blood pressure. But you will need to subtract 10/5 to this to give you the equivalent target using your home blood pressure machine.