Online Blood Pressure Project - Checking Blood Pressure

Checking Blood Pressure

As you might imagine, checking blood pressure accurately is crucial to the effective monitoring of someones health. To make this meaningful and safe, the blood pressure readings must be accurate.

The accuracy of blood pressure measurement is dependent upon two main factors.

  • The equipment used.
  • The technique with which blood pressure is measured.



The team have spent time discussing blood pressure monitors with the main companies who produce these devices. Encouragingly, all of the companies have similar advice regarding their machines.

In order to be eligible for the service we advice that the following information is followed

1) Please check that your blood pressure machine is validated for use at home. The British Hypertensive Society has developed a list of validated monitors. The list can be found by following the link below. It is important to remember that you do not need an expensive monitor to accurately measure your blood pressure. Click here for the list.

2) Check that your machine is less than three years old. All of the companies who responded to our request for information (this includes Lloyds, Omron and Kinetic) explained that their machines are under warranty for three years and should not need calibration (checking to ensure that readings are accurate) in this time period. If you have concerns about the accuracy of your machine then we will offer, throughout the year, the opportunity to check your machine against one of our machines in the surgery. It is important to note, that after three years, there is no reason to believe your machines are no longer accurate, but that the companies will not vouch for it unless stated in your warranty / documentation.

3) Check you have the correct cuff size. It is really important that when using your blood pressure machine that you have it connected to a cuff that is the correct size for your arm. Incorrectly fitting cuffs give false readings. It is also necessary that you fit it correctly on your upper arm, as we demonstrate below on our “How To Take Your Blood Pressure” video. The table below explains how to ensure the cuff is the correct size. You can also discuss with your local pharmacist.


Upper Arm Measurement (cm)        Cuff Size Required

18 - 22 cm                                                           Small

22 - 32 cm                                                           Medium

32 - 45 cm                                                           Large


Most blood pressure machines on the validated list are relatively inexpensive, but we do have machines in the surgery that are suitable for loaning should you wish to do so. If you wish to loan a machine for use in the project then please email: This email is NOT suitable for clinical questions.


Technique - How To Take Your Blood Pressure

The following video describes the best way to measure your blood pressure. The principles are summarised here in written form.


How Often Should I Check My Blood Pressure?

The online blood pressure management service requires you to check blood pressure in accordance with the best practice known at present.

During Your Review Month

During your review month we ask you to pick seven days upon which you will record your blood pressure. These do not need to be consecutive but should be undertaken and submitted to the practice before Day 21.

During Each Review Day

On each of your seven review days we will ask you to select two different times or sessions during the day, often morning and afternoon.

During Each Review Session

Each morning / afternoon session we will ask you to take your blood pressure three times, separated by about one minute.


Each session you will take three readings, and as we ask you to check on two separate occasions a day you will be submitting six readings a day.


How Do I Submit My Readings On The Software?

Please follow the explanation found on the using the software section of this website.


What Happens To My Readings?

After you have submitted all seven days worth of readings, they are written to a PDF file and are securely stored until the practice views them.

Average Blood Pressure.

We are interested in the average of your blood pressure readings. This is calculated utilising the best guidance issued by NICE and is summarised as follows.

  • Discard Day 1 readings.
  • Pick the “best” readings from each of the remaining “sessions” (i.e. 12 results).
  • The best readings are then averaged to calculate your average blood pressure for the week.


What Happens If I Submit Readings That Are Too High or Too Low?

Our main goal is to help you achieve a blood pressure that lies within a specific target range. For most individuals this means we aim to achieve a top figure (known as a systolic blood pressure) of between 100 and 140 and a bottom figure (known as a diastolic blood pressure) of between 60 and 90.

Sometimes, for a variety of reasons, our blood pressure lies outside of this target range and in most instances does not need any immediate concern or management. However, there are instances where it is important for us to act upon blood pressure readings and the software has been designed to pick up these “unusual” readings. This may be because the figures have been inputted incorrectly, or the figures submitted have fallen substantially outside of our clinical safety range.

The checking process begins the moment you confirm that your blood pressure readings have been inputted correctly.


High Readings

To ensure both yourself and the practice are alerted to readings that are well above our target blood pressure range we have set two alert levels. These levels are based upon our clinical practice at Lion Health and guidance set out by the British Hypertensive Society and NICE.

  • Extreme High Reading. A reading triggering this alert needs prompt assessment by a health care professional and you will be informed about how to arrange this. Such a reading will also cause the software to block you from further blood pressure submissions until this has been rectified. See below.
  • Very High Reading. A reading triggering this alert does not need immediate action but is sufficiently high to warrant closer monitoring. If two further readings, on different days, trigger this alert then you will be asked to attend the surgery for clinical review. If you submit three very high readings then you will be blocked from the software until this has been rectified. See below.

Low readings

You have probably heard people say the lower your blood pressure the better. However if your blood pressure drops to being too low, it may make you feel unwell. Lightheaded episodes would be the most common symptom which could make you unsteady on your feet. This could be caused by your medication dose being too high, and therefore needs adjusting. A reading triggering this alert needs prompt assessment by a health care professional and you will be informed about how to arrange this. Such a reading will also cause the software to block you from further blood pressure submissions until this has been rectified. See below.

Getting Blocked

As outlined above, there are occasions when you may get blocked from the software because we have identified readings that need prompt action and cannot wait until the end of your review month. If this happens, we ask that you:

  • Contact the surgery within 24 hours. If this happens during weekends or bank holidays, you can either call the Out of Hours line or if the next working day is within 24 hours, please wait and call Lion Health.
  • When doing this, please state that you are taking part in the “Online BP Project” so we can see you in an appropriate appointment.

This project is designed to safely manage blood pressure related issues. If however you become clinically unwell during the project we ask that you use the surgery as you would normally to seek medical advise as you feel necessary.


What My Weekly Blood Pressure Average Means

Assuming that your blood pressure readings are close to our target range, you will be provided with a blood pressure average. The following video explains the meaning of your blood pressure There are further educational resources that can be found by following this link.

. In this section we discuss the following:

  • Why blood pressure control is important.
  • The management options available should your readings be higher than we would like.