Compare measured blood pressure values with the measurement of the (general) practitioner

It’s one of the most frequently asked questions we get. The blood pressure values measured by the blood pressure monitor do not correspond to the measured value of the (general) practitioner. Does my blood pressure monitor measure accurately?

We can answer the question with “Yes”. The blood pressure monitor you purchased measures accurately. The blood pressure monitors we provide are clinically validated. This means that the blood pressure monitors are extensively tested and comply with at least 1 of the 3 international protocols. From the factory, the blood pressure monitors are directly “calibrated” for reliability and accuracy. It can therefore be assumed that the blood pressure monitor measures accurately right away. Without calibration, the blood pressure monitor cannot be delivered.

The values measured by your blood pressure monitor may be different from the values measured by the (general) practitioner or another, clinically validated, blood pressure monitor. You cannot directly compare the measured values. That’s comparing apples to oranges.

 

Different times, different measurements

Blood pressure fluctuates throughout the day. Every moment the blood pressure reading is different. Within 30 seconds, blood pressure can be 20 points higher and then 30 points lower again. It depends entirely on the situation. For example, moving and talking has an effect. The same goes for tension or anxiety. For example, unconscious nerves for a doctor. As a result, the measured value at the doctor’s office may be higher than the measured values at home. This is also known as the “white coat effect”.

But this is also possible in reverse. Measured values at home may be higher than measured values at the general practice. This is called hidden hypertension. This hypertension manifests itself only in the moments of rest.

It is recommended to measure in the morning (before 10:00) or in the evening (after 19:00). At those times, blood pressure is usually “calmer” and therefore more accurate to measure.

Therefore, comparing a blood pressure reading measured in the morning with a blood pressure reading measured in the afternoon is of no use.

 

Age of a blood pressure monitor.

The age of a blood pressure monitor has an effect on the measured values. A blood pressure monitor is nothing more than a pump. This pump inflates the cuff and then deflates it. Over time, the quality of the pump decreases. After all, wear takes place. This prevents the pump from achieving the high pressure levels. It will turn off sooner, causing the measured values to be lower. After all, to determine high blood pressure, the pump must be able to reach high pressure levels. As a result, you will see the meter rise.

A home blood pressure monitor is used much less than the blood pressure monitors at the general practices. The meters of the general practices are used several times a day. A lot of wear and tear takes place there. Manufacturers suggest replacing a blood pressure monitor over time. A blood pressure monitor has a lifespan of about 5 years and less with a lot of use. For home use, a blood pressure monitor can last longer. After all, at home you measure considerably less.

General practices and hospitals must have blood pressure monitors checked annually. Unfortunately, this often goes wrong. One checks the blood pressure monitor for functioning properly, but cannot calibrate it. Subsequent calibration of a digital blood pressure monitor is not possible. A digital blood pressure monitor can only be calibrated directly at the factory.

 

The (family) practitioner measures with an analogue blood pressure monitor with stethoscope

There are doctors who say that the old, analog, way of measuring blood pressure is the most accurate way. This is partially true. There are doctors who can measure blood pressure very accurately by ear. In this case, the doctor listens with a stethoscope and uses a second hand to determine the upper and lower pressure.

The downside of this method of measurement is, that it’s very dependent on the doctor’s hearing. If the doctor can’ t hear it well, there can be a big difference in the measurement. For this reason, many doctors are switching to a digital blood pressure monitor. They use the same blood pressure monitors that you can buy from us.

 

How do you correctly compare blood pressure readings?

There is only one correct way to compare measured blood pressure readings. When you are going to measure, you need to calculate an average blood pressure of 3 measurements. An average reading will reflect blood pressure more accurately. In order to compare, measurements need to be made in turn. First A, then B, then A, etc. From the measurements, you take an average.

What often happens is that the 1st measurement is mostly higher. The measurements that follow are usually lower. An average of 3 measurements ensures that this effect is minimized.

Even then you will see that there is a difference. However, this difference will be small and falls within clinical validation. This is accepted within medical science and is also described within the Dutch standards for general practitioners. The difference should then be no more than 5 to 10 mmHg of upper pressure.