This site is intended for health professionals only

At the heart of general practice since 1960

Measure blood pressure in both arms, GPs advised

GPs taking clinic blood pressure readings should take measurements from both arms, say UK researchers.

The study

Researchers from Birmingham and Oxford analysed data from 710 patients who attended a hypertension clinic at University Hospital Birmingham. At a pre-clinic appointment, they had blood pressure measured in one arm, and then the opposite arm immediately after. They were then fitted with a 24-hour ambulatory blood pressure monitor to the non-dominant arm, unless the difference in systolic pressure was over 20 mmHg or diastolic pressure over 10 mmHg, in which case the monitor was fitted to the arm with the higher reading.

The findings

There was a mean difference of 25.1 mmHg between the arm with the highest reading and the ABPM, compared with a mean difference of 15.5 mmHg between the arm with the lowest reading and the ABPM. When the inter-arm difference was calculated and compared to the ABPM, they found no significant association.

What does it mean for GPs?

The authors concluded that the study highlights ‘the limitations of single clinic readings, which are not accurate compared with ABPM or other forms of prolonged monitoring.’ They added that it reinforced NICE guideline advice that blood pressure should be measured in both arms and should be repeated if the difference in readings between the arms is more than 20 mmHg. They finished by saying that clinicians should ensure ‘the differences in right and left arm pressures are checked by repeated measures in both arms.’

Expert comment

Dr Terry McCormack, GP in Whitby and member of the NICE guideline development group for hypertension: ‘The study points out that unless you are using equipment which simultaneously takes BP in both arms you need to do a series of tests to be accurate. This is the perfect way to take blood pressure, but it remains to be seen if it is taken up in practice.’

BJGP 2013, available online 28 January

Readers' comments (3)

  • Tom Caldwell

    I can think of no time implications of (at least) doubling the amount of time it takes to do the patients blood pressure. Assuming of course that the measurements do not need repeating, and the patient does not need any explanation of why their blood pressure is being taken so many times in both arms and of course that the patient came with their clothing already removed adequately to perform a BP reading in both arms whilst screening for dementia........... no can't think of any way we will struggle to achieve this.

    Unsuitable or offensive? Report this comment

  • Well I think we should measure temperature in both ears as well as it can be very different!

    Unsuitable or offensive? Report this comment

  • and not forget checking the temp in the arse as it will be more different still!

    Unsuitable or offensive? Report this comment

Have your say