While thinking about Home Blood Pressure Monitors, the first thing that comes to mind is how accurate are they. Which one would be better home based wrist or upper arm monitors? Is the reading comparable to the readings at the doctor’s office?
If we just take the device, then home based monitors are pretty good and the readings in most cases are very close to professional Sphygmomanometer. However, a device is just one factor, accuracy also depends on how you take readings. For sure professionals do a better job. However, if you take proper care you can get similar readings at the comfort of your home. Also, it is much easier to keep regular track if you have a device at your home.
American Heart Association stills recommends an upper-arm monitor. Wrist and finger monitors are not recommended because they provide less accurate readings. Historically this was true; however, now Wrist monitors are as accurate as arm monitors.
Factors that affect Accuracy
- Cuff Fitting: The most important aspect for blood pressure monitor is the cuff fitting. For an upper arm model, if the cuff fitting is loose or tight, then it does not show accurate readings. Most of the monitor cuff comes in standard sizes (Small, Medium, Large and Extra Large) such as LifeSource UA-767. Some manufactures creates cuff that are suitable for multiple sizes such as Omron ComFit Cuff for BP760 or BP785n/BP786. To get the proper size for you, measure your arm with a measuring tape. Take the measurement between the midpoint of the upper arm and elbow.For wrist monitor, the fitting is little less important as there is not a wide variation in the wrist size. However, still it’s a better idea to measure your wrist size and compare it with the sizes the monitor supports.
- Proper Positioning: Another important aspect for getting accurate readings is the positioning. Whether it is an upper arm or wrist, they should be at heart level. This is the main issue with the Wrist Blood Pressure monitors. It’s hard to keep them at the required level. Hence, Wrist monitors are more prone to errors with respect to positioning and they are considered less accurate. However, If the wrist monitors are positioned correctly, they will show the accurate readings. There are certain wrist monitors that guide you to position the device correctly. The Omron 7 series(BP652), has one such feature. They have in-built positioning sensors, that beeps till the device is in correct position.
- Validation and Calibration: A good thing to check for monitors is their certifications. Whether the device is validated and approved by a standard body such as:
- AAMI (American Association of Medical Instrumentation)
- BHS (British Hypertension Society)
- ESH (European Society for Hypertension)
This ensures that your device is calibrated and validated. If the device is not calibrated, then even if you take proper precautions it doesn’t help. It is also recommended to get your blood pressure monitors calibrated after every two years to get accurate readings.
Historically why Wrist Blood Pressure monitors were less accurate ?
Wrist monitors are more prone to errors if directions are not followed properly. The main reason: The arteries around the arm is thick and resides deep in the forearm, allowing the monitor to measure blood pressure accurately. In contrast to an upper arm, the wrist arteries are thin and not deep in the skin thus hinder the process of blood pressure.
Precautions and steps to get accurate results
Other than the device and taking the readings, you also need to take few precautions for getting accurate reading. Precautions such as not to take reading immediately after exercise, eating food etc. For Details you can refer the article: How to measure blood pressure measurement.
After the purchase, it’s a good idea to take the device to your doctor and he can compare the blood pressure using the hospital Monitors and your’s monitor to check for accuracy.
No doubt both wrist and arm are accurate monitors, because both the models need to meet stringent specification such as Pressure: +/- 3 mmHg (millimetres of Mercury), Pulse: +/- 5% of display reading. However, upper arm monitors are still much easier to position correctly.
Now that we are clear about the accuracy, if you are on the go always, or might have a big arm, then wrist blood pressure monitors are good for you.
If you like large display, ease of positioning then go for Upper arm blood pressure monitor.
As per budget, both upper arm and wrist come in competitive pricing based on features.
You can also check our Recommendations and Reviews on few top Blood Pressure Monitors.