Blood Pressure Measurement Mistakes and Misdiagnoses

A doctor’s appointment can start raising your blood pressure long before you ever reach the exam room. It may begin the moment you wake up. Do you have time for a shower? What should you wear? Can you eat breakfast or do you need to fast in case there’s a blood test. Then comes the drive, which may involve traffic and the worry that you’ll be late. If your appointment is at a hospital or large clinic, there’s often the added stress of finding a parking space and getting inside on time. Let’s not forget the apprehension around a new diagnosis or the discomfort from an existing condition. All that stress can create blood pressure measurement mistakes before you even get to the doctor’s office.

If you’re running behind for any reason, the tension builds. By the time you reach the waiting room, you may already feel rushed or keyed up. Then the wait begins. Will you be called back in five minutes—or will it be half an hour or longer?

What Happens When You Are Taken Back?

Eventually, your name is called. The routine begins almost immediately: step on the scale, temperature check, oxygen saturation—and then, almost without pause, blood pressure measurement. Few people are given time to sit quietly beforehand. Has anyone ever asked if you would like to stop in the restroom before taking your blood pressure? I didn’t think so, and yet this is surprisingly important.

Will you be offered a chair with an arm rest? or will you be stationed on an exam table. You may be asked questions while the cuff is inflating. You might even feel pain from a tight cuff. All of these factors—stress, a full bladder, conversation, discomfort—can raise blood pressure readings. All this is happening while you are feeling vulnerable and out of control. If you question technique or procedures, you will likely be corrected or criticized and that can raise blood pressure.

Timing is Critical To Avoid Blood Pressure Measurement Mistakes:

One reader’s experience illustrates just how misleading a stressed-out reading can be.

Q. My blood pressure was always high when it was taken at the beginning of a visit to the doctor. The second reading, at the end of the visit, was usually normal. But I discovered it wasn’t really white-coat hypertension one day when I arrived early for my appointment.

The hour-long drive had been stressing me out. When I allowed enough time to get there 15 minutes early, I was fine, and so was the first BP reading. That’s a lesson learned for all of my meetings and appointments, not just the medical ones!

A. Stress can definitely raise blood pressure. Even the very mild stress of having a full bladder can ratchet the reading up. We appreciate the reminder to factor in a bit more time to our appointments so we don’t end up under pressure.

The guidelines recommend that people be allowed a few minutes to sit quietly before blood pressure is measured. Few medical practices follow that recommendation, though. Your solution is excellent.

Blood pressure measurement mistakes are common! No one seems to care, even though this key biological metric is really important.

Who’s Measuring Your Blood Pressure?

Blood pressure is an important risk factor for cardiovascular disease. In recent years the recommended threshold for treating hypertension has been lowered. Health professionals are expected to help people get their systolic blood pressure below 130 and their diastolic blood pressure readings below 80. So-called normal blood pressure is 120/80 or below.

There was a time when nurses and doctors measured blood pressure. They still do…occasionally. But in a typical clinic today, the chances are good that blood pressure will be measured by a lower-paid technician.

In our experience, many of these individuals have not been adequately trained. Measuring blood pressure correctly is not as simple as it appears. Doctors and nurses sometimes make errors. The technicians we have encountered in recent years rarely get the entire process right—even at top-notch medical facilities where administrators should know better.

As a result, blood pressure measurement mistakes are common.

Cuff Size: One of the Most Common Blood Pressure Measurement Mistakes!

Researchers from Johns Hopkins University reported on a fascinating randomized crossover trial to determine the “Effects of Cuff Size on the Accuracy of Blood Pressure Readings” (JAMA Internal Medicine, August 7, 2023). The authors examined 195 adults with a wide range of arm sizes to see what happens when a single standard-size blood pressure cuff is used on everyone.

People with thin arms ended up with a reading lower than their actual blood pressure. In contrast, those with large arms had blood pressure readings substantially higher when measured with the standard cuff compared to a large cuff.

If people who needed an extra-large cuff were measured with a regular-sized cuff, the average blood pressure reading was 144/88. When these same individuals were measured with an appropriately-sized cuff, the readings averaged 125/79. The wrong-size blood pressure cuff for such individuals could lead to unnecessary treatment and more adverse drug reactions.

Please hit your internal pause button. When was the last time a technician (or a doctor or nurse for that matter) actually measured the circumference of your arm? I would bet it would be rare to never.

Everyone is in a hurry these days and most exam rooms do not have a way to measure arm size. More important, most exam rooms do not come equipped with various-sized blood pressure cuffs.

The Authors of This Study Introduce the Problem:

“Hypertension is the leading cause of cardiovascular disease worldwide. Accurate measurement of blood pressure (BP) is used to screen for hypertension and to diagnose and treat hypertension. Although there are several preparatory and positioning steps required for accurate BP measurement, individualized selection of appropriate cuff size is often overlooked, despite clinical practice guidelines.”

In other words, doctors have been told exactly what they are supposed to do prior to measuring a patient’s blood pressure. Many of those steps are ignored, especially the part about selecting “appropriate cuff size.”

Here is the researchers’ bottom line:

“Using a regular BP cuff size for all individuals regardless of arm size resulted in strikingly inaccurate BP readings with an automated device; a renewed emphasis on individualized BP cuff selection is warranted, particularly in individuals with larger arm sizes.”

Let’s be really honest for a moment. A lot of Americans now come with “larger arm sizes.” We are a nation that is largely overweight. If a technician uses a “standard” cuff size on someone with a larger arm circumference, it is likely that the BP reading will higher than it actually should be. That could lead to an extra blood pressure medicine and that could lead to additional adverse drug reactions.

The SPRINT Trial vs. Office Readings:

Research published in JAMA Internal Medicine (Oct. 12, 2020) compared office blood pressure measurements to the careful readings obtained in the SPRINT research trial. More than 3,000 patients participated. In the research setting, blood pressure was measured according to strict professional guidelines. The same patients had their blood pressure measured during routine doctor visits.

There was surprising variability between the numbers obtained in the two settings. Many participants had higher readings in routine clinical practice—differences large enough to lead to misdiagnosis and unnecessary treatment.

Blood Pressure Measurement Mistakes: Why Routine Readings Run High

The authors explained:

“Our results are generally consistent with prior studies that have demonstrated that BPs measured using proper technique are typically 5 to 15 mm Hg [mercury] lower than the corresponding BPs measured in the routine clinical practice settings. Improper BP measurement technique is likely the underlying cause of higher BPs in routine clinical practice compared with trial measurements. Nearly all of the protocol deviations in routine practice (eg, lack of rest period prior to readings, talking during measurement, and arm not supported) are associated with overestimation of BP.”

A Commentary on Blood Pressure Measurement Mistakes:

A commentary in the same issue of the JAMA Internal Medicine (October 12, 2020) noted that routine blood pressure measurements in the office setting don’t often follow established guidelines. People are rarely given 5 minutes of quiet time before their blood pressure is measured three different times.

The cuff size is almost never matched to the size of the patient’s arm and people may not be positioned with their feet on the floor, their back supported, and their arms supported at heart level.

The researchers suggest that blood pressure measurement mistakes might have contributed to the problem. The authors emphasize that proper blood pressure measurement technique is crucial.

The authors note:

“Blood pressure measurement in the office setting has been the primary method used for managing hypertension. These data underscore what has been reported in the literature for decades—routine office BP and research-quality office BP are different measures—and highlight the major gap between clinical practice and research studies in the management of hypertension.”

We now know that there are lots of blood pressure measurement mistakes made in the doctor’s office or clinic.

Readers Share Their Stories About Blood Pressure Measurement Mistakes:

We regularly hear from readers about painful cuffs, rushed measurements, and wildly fluctuating readings.

Gigi writes:

“I have so much pain in my arm from a tight cuff when they check blood pressure. The nurse tells me to lower my arm, and rest my hand in my lap. This is wrong. If I try to place it at heart level, I am reprimanded.

“I can go in perfectly normal, and my BP will go up to 190 because they continually keep taking it the wrong way. Last week, the nurse took it 8 times in a row until I refused to let her touch me. My BP goes up as soon a the cuff begins to tighten. It’s like a panic attack, and nothing helps.”

Gayle has also had problems with automated blood pressure equipment:

“The new auto BP cuffs at the doctor’s office hurt like a *#*, and suddenly I have high blood pressure and am put on a medication to treat it. The drug makes me cough– not acceptable!

“I quit that med, and when next at the doctor’s office months later, insisted on manual reading. Big surprise, my BP was back to its usual 116/70. Gee I guess pain does raise your BP!”

Here is why waiting several minutes prior to BP reading is essential! Mary shares this story:

“My husband was at the doctor’s office and his first BP reading was 158. The doctor was very concerned but my husband said wait. After they had talked, my husband asked her to do another reading. It was 101, this was 15 minutes later! He dropped 57 points in 15 minutes.”

Preventing Blood Pressure Measurement Mistakes:

We have written extensively about how blood pressure measurements should be taken. Here is a link to an article with practical tips:

Seven Mistakes to Avoid When Measuring Blood Pressure!
Do you avoid mistakes when measuring blood pressure? We are constantly amazed at how many technicians incorrectly take blood pressure readings. Here are tips to help you eliminate errors.

You may also find this article of value:

What’s the Best Way to Measure Blood Pressure?
What’s better, blood pressure readings at the doctor’s office or at home? A new study will surprise many health professionals. The results should change attitudes!

Our eGuide to Blood Pressure Treatment provides additional insights on how to avoid blood pressure measurement mistakes. It also offers nondrug options for helping to control high blood pressure. Here is a link.

Before Your BP Is Taken: A Simple Checklist

To reduce blood pressure measurement mistakes, consider this checklist:

• ☐ Arrive early so you are not rushed
• ☐ Use the restroom beforehand (a full bladder raises BP)
• ☐ Sit quietly for at least 5-10 minutes before measurement
• ☐ Ask not to talk during the reading
• ☐ Make sure your back is supported and feet are flat on the floor
• ☐ Your arm should be supported at heart level
• ☐ Ask whether the cuff size matches your arm circumference
• ☐ If the cuff is painful, say so

Advocating for accurate measurement is not being difficult—it’s being responsible.

Here are some guidelines to help you make sure you get the right size blood pressure cuff (American Journal of Hypertension, Nov. 2022):

Mid-arm circumference:

• Less than 26 cm (1o.2 inches) = Small Adult Size Cuff
• 26-34 cm (10.2 to 13.4 inches) = Regular Adult Size Cuff
• 34-44 cm (13.4 to 17.3 inches) = Large Adult Size Cuff
• More than 44 cm (17.3 inches) = Extra Large Adult Size Cuff

Please share your own experience with blood pressure measurement in the comment section below. If you think this article could help a friend or family member, please send it along.