When doing this type of a comparison, it is very important that the measurements are taken in a certain manner in order for the reading on the OMRON monitor to be accurate. The OMRON monitor uses oscillometric technology that measures the vibration of the blood as it moves through the arteries. The doctor is using a different method of measurement and listens to the sound of your heart. It is necessary for the doctor to take the first measurement using the OMRON monitor. The brachial artery is fully open and not restricted so vibration of the blood is accurately measured. It is also important to note that the different test methods may give slightly different readings due to the test methods or due to the normal fluctuation in blood pressure.

There are many reasons why blood pressure readings may seem high. Below are some of the common reasons and the estimated ranges of how much readings can vary. It is important to ensure you are using the monitor as it was intended, so please make sure you are following the directions in the instruction manual, or call our consumer support line at (877) 216-1333 if you have questions. It is also important to note that if you can continue to see high readings, discuss with your doctor or a medical professional -- it is possible that your blood pressure is actually higher than what you believe it to be.

Factors Affecting Accuracy of Blood Pressure Monitors¹

Factor	Magnitude of systolic/diastolic blood pressure discrepancy (mm Hg)
Talking or active listening	10/10
Distended bladder	15/10
Cuff over clothing	5-50/
Cuff too small	10/2-8
Smoking within 30 minutes of measurement	6-20/
Paralyzed arm	2-5/
Back unsupported	6-10/
Arm unsupported, sitting	1-7/5-11
Arm unsupported, standing	6-8/

1 Handler J, The Permanente Journal 2009; 13:3:51-54

It is quite normal for people's blood pressure to change throughout the day and night, or in different settings where you may take your blood pressure. Many things, such as stress levels, food or drink intake, activity levels, even time of day can all affect a person's blood pressure reading at any given time. So, it is possible that you may just be seeing normal fluctuations in blood pressure.

However, below are some common situations that can lead to inconsistent or inaccurate readings:

Using the wrong cuff size for your arm

Just because the cuff may fit around your arm does not mean it is the right size cuff for you. The correct cuff size is directly related to the circumference of your arm. To get accurate readings, it is important that you are using the correct sized arm cuff. To determine your arm size, use a cloth tape measure and place midway between your elbow and your shoulder around the circumference of your upper arm. Wrap the tape measure evenly around your arm. Do not pull the tape tight. Note the precise measurement in inches. Select an OMRON home blood pressure monitor with the right size of cuff included, or if you already have the monitor, and need a different sized cuff, contact our consumer support line at 877/216-1333, and they can assist you to purchase the right size accessory cuff for your unit. View a short video on selecting the right size cuff.

Not using the cuff correctly

Make sure you are wrapping the cuff around your arm in the correct position. After wrapping the cuff around your arm, check the location of the brachial artery marker. The air tube should run down the center of your arm. The cuff should not be wrapped too tight or too loose. Look at the instruction manual for the monitor to get more detailed instructions on the specific cuff included with your unit.

Activities right before taking a measurement

Avoid eating, drinking alcohol or caffeinated beverages, smoking, exercising and bathing for 30 minutes prior to taking a measurement. It is also best to rest for 15 minutes before starting the measurement. Avoid taking a measurement during stressful times. Take the measurement in a quiet place.

Incorrect body position or moving too much

Sit in a chair with your feet flat on the floor. Rest your arm on a table with your palm facing upward. The cuff should be level with your heart. Do not talk or move during the measurement.

Timing of taking measurements

Try to take readings at the same general times each day (for example, once in the morning and once at night) for comparison purposes.

D-Ring Upper Arm Cuff

A D-ring cuff is a standard type of blood pressure cuff that you would usually see in your doctor's office. It is a cuff where the user loops one end of the cuff through a metal ring, then fastens it to the arm. D-ring cuffs come in different sizes of small, standard and large. It is important to pick out the right size cuff based on your individual arm circumference. Please see the questions in this OMRON FAQ regarding the different types of cuffs and how to measure your arm circumference.

Expandable ComFit Upper Arm Cuff

The OMRON ComFit Cuff is a pre-formed upper arm cuff that expands to fit both regular and large sized arms (upper arm circumferences between 9 and 17 inches). It is designed to ensure more comfortable, accurate readings.

Wrist Cuff

A wrist cuff is similar to an upper arm cuff; however you can wrap it around your wrist instead of your upper arm.

Oscillometric technology measures the vibration of your blood traveling through your arteries and converts the movement into digital readings.

Both readings are important. One measures your blood pressure during a heart contraction and the other measures blood pressure between heart contractions. For your particular situation, you should discuss both measurement results with your doctor.

Your Heart Rate is the number of times your heart beats in the span of one minute, and is measured using EKG technology. Your Pulse Rate refers to how many times your arteries expand and contract within one minute, and is measured using a blood pressure monitor. Heart Rate and Pulse Rate are calculated differently, and there may be a difference between both values. For more information, please refer to your Instruction Manual.

Digital monitors measure blood pressure oscillometrically rather than by auscultation. In auscultation, stethoscopes are used to take blood pressure by listening for specific heartbeat sounds which the doctor then uses to determine systolic and diastolic pressures. Oscillometric technology measures the vibration of blood traveling through the arteries and converts the movement into digital readings.

OMRON digital blood pressure monitors use the oscillometric method of blood pressure measurement. An oscillometric monitor does not need a stethoscope so the monitor is simple to use.

It is also important to note that Home Blood Pressure monitoring allows you to monitor frequently and share the results with your doctor if you desire.

The ComFit cuff is pre-formed to wrap easily around your upper arm. It features 360º around the circumference of your arm to help reduce measurement errors and ensure inflation over your brachial artery. The D-Ring cuff is a soft contoured cuff that is designed for more comfortable measurement. This style is typically seen in a doctor’s office. You loop one end of the cuff through the D-shaped metal ring, put your arm through the cuff and then fasten the end around the arm. Both cuffs fit a standard- to large-sized adult arm. 9” to 17” in circumference.

When purchasing an at-home blood pressure monitor, it is important to know your proper cuff size. To determine your arm size, use a cloth measuring tape and measure the circumference of your left upper arm midway between your elbow and shoulder. The blood pressure cuff must be neither too tight nor too loose to help ensure accurate readings, providing you with an accurate picture of your heart’s health.

How to assemble the D-Ring Cuff

For most models, the warranty coverage for the arm or wrist cuff is one year. Cuffs will need to be periodically replaced throughout the life of the monitor. When purchasing a replacement cuff for an upper arm unit, please be certain to measure the circumference of your arm to purchase the correct cuff size. Please check the instruction manual for your specific unit. Electronic versions of the instruction manuals can be found in the Support section.