Clinical validation - what is it and what should you consider?

Clinical validation cerifies the measurement accuracy of the monitor and tests are performed with selected subjects who meet certain criteria, including blood pressure classification, age, sex, and pre-existing conditions. One of the most important factors to consider is the patient's access to accurate and reliable blood pressure monitors with validation protocols. At Microlife, we ensure all blood pressure monitors are clinically validated for accuracy, through strict review processes from international institutes and societies in the field of blood pressure, such as BISH, ISH or ESH.

What are validation protocol standards?

A blood pressure monitor validation study is a clinical study to verify the accuracy of a blood pressure monitor. The protocol for this validation study is established by a collaboration of the International Standards Organization (ISO), European Society of Hypertension (ESH), the British and Irish Hypertension Society (BIHS) and the Advanced Association of Medical Instruments (AAMI).

What are basic validations?

Basic validation is performed on a group of subjects that is representative of an "average population without any diagnosed pre-existing conditions". The larger the number of subjects, the more statistically significant, thus more reliable, the validation test is. Therefore, basic validations are conducted based on the protocols of the following institutes and organisations. 

*There are differences between the test protocols of the institutions; for example in respect of the group size.

Another difference is the blood pressure ranges examined. The blood pressure ranges in which the blood pressure monitors are checked for measuring accuracy differ depending on the test protocol (see graph). The broader the range is, the better the devices are checked to be reliable at extremely low or extremely high blood pressure.

The importance of special patient validations

Medical standard authorities require that a blood pressure monitor may only be recommended for such a special patient group if it has been validated for this specific group. This is because that blood pressure monitor is validated in "regular subjects" and may not give accurate reading when used e.g. during pregnancy or when used in children, elderly or diabetes patients. Microlife blood pressure monitors have passed several of these callenging validations so that they can now be recommended for all of the following special patient groups.

Diabetes
Patients with Diabetes Mellitus type 1 and 2 may have stiff arteries that can affect the blood pressure measurement. A recent validation study in diabetes patients type 1 and 2 showed Microlife monitors are accurate when used in this patient group.

Pregnancy and Pre-Eclampsia
Most oscillometric blood pressure monitors underestimate blood pressure in pre-eclampsia. For this reason, oscillometric blood pressure monitors may only be recommended for use in pregnancy when specifically tested in this special patient group. Microlife allows pregnant women to measure their blood pressure at home which could reduce the number of hospital visits and may help to make motherhood safer.

End-stage renal disease
Patients with moderate to severe renal disease have a very high incidence of hypertension, paired with stiff (calcified) arteries. As automated measurements can be influenced by stiff arteries, a special validation is required before blood pressure monitors can be recommended for use among patients with end stage renal disease.

Children
As children have a high respiration rate and have difficulties in sitting still, one needs a blood pressure monitor with a high-quality algorithm that can filter out these artefacts. In addition, a wide cuff range is needed that covers very small to large arm circumferences. 
Microlife blood pressure monitors have proven to cover all these aspects and therefore can be recommended for children and adolescents aged 3 to 18 years (Microlife WatchBP Office and O3 Ambulatory) and 12 to 18 years (All Microlife automatic upper arm blood pressure monitors and WatchBP Home).

Cuffs, as important as the blood pressure

Validations are generally performed with the standard cuff-size of the respective device model. However, Microlife has put extra attention to validations with all type of cuff sizes and types, including soft cuffs, rigid cuffs and wide-range cuffs. As there is a large increase of people who are overweight, validations of XL cuffs are becoming more important. In order to ensure that correct blood pressure values are obtained in these patients Microlife has developed an XL-cuff which has been validated for accurate blood pressure measurement in patients with large arm-circumference. Microlife is the only solution provider for home blood pressure monitors with an explicite validation for the XL cuff and comes highly recommended for overweight patients.

Click here to read more about cuff types and sizes.

Further studies

Microlife AFIB, the atrial fibrillation (AF) detection

In addition to the validations mentioned above, there are also studies conducted to other innovative Microlife technologies and measurement methods. They work with new technologies or measuring methods, which are used in blood pressure monitors. Well-known institutions, such as the universities of Oxford, Athens, Rome, Maastricht, Hong Kong and New York, have published clinical studies regarding the Microlife AFIB technology, which is applied exclusively in Microlife upper arm blood pressure monitors. All studies have shown that Microlife AFIB can automatically detect dangerous atrial fibrillation - the most frequent cause of a stroke - even with high precision. Microlife AFIB as of today, is worldwide the only approved technology for AF screening during blood pressure measurement. (MDD93/42/EEC, MedDEV 2.7.1., FDA)

Read more about AFIB

Microlife MAM - 3 measurements with 1 click.

Other studies investigated the value of multiple blood pressure measurements – a technique that is also automated in the Microlife models (so-called MAM technology). In these studies interval times between the individual measurements were observed in order to obtain valid measuring results at the end. A pause time of 15 seconds for oscillometric measurement was determined sufficient as a reference value, as is also the case with the MAM technology.

Read more about MAM

Click here to download this information as a pdf.