Most digital blood pressure monitors use the oscillometric method. Each manufacturer uses its own principles for analyzing the measurement signals and to determine the corresponding systolic and diastolic values. Several studies have reported differences in accuracy, sometimes significant, between blood pressure monitors.
iHealth has long experience in designing blood pressure monitors. The high accuracy of the iHealth blood pressure monitor is confirmed by extensive clinical studies carried out by independent medical centers in accordance with the highest international standards.
Each manufacturer uses its own principles adapted to the "standard" population. One particular blood pressure monitor will better suit one person than another. Similarly, two doctors with different skills for observation with their stethoscope may obtain different blood pressure values.
The difference in blood pressure can also be explained by the variations that occur between two measurements. In fact, it is difficult to make consecutive measurements under the same conditions. This type of test usually gives different results due to the instability of physiological conditions and the influence of secondary factors (discussion, noise, movements, etc.).
If you want to compare two blood pressure monitors better, you need to eliminate as many sources of interference as possible. Take measurements without external disturbances by following the precautions for use. Take measurements under similar conditions, at the same time of day. Be sure to relax between measurements and wait at least three minutes before beginning. Take several measurements with the same device and compare the averages obtained. Only by carefully following the instructions above will you be able to determine the magnitude of the differences. However, these comparative measurements will not determine which of 2 devices tested is the most accurate.
Feel free to contact our technical support if you have any doubt about the performance of your device.
*credit to Sylvain of iHealth Labs EU
https://helpcenter.ihealthlabs.eu/hc/en-gb/articles/115005936085-iHealth-View-BP7S-I-compared-the-results-with-another-device-The-results-are-different-Why-