Yes, you can take blood pressure on the forearm, but the readings will typically run higher than upper arm measurements. The American Heart Association considers the upper arm the standard location for blood pressure measurement, and forearm readings are generally reserved for situations where using the upper arm isn’t possible. If you do measure on the forearm, expect systolic readings (the top number) to be about 4 mmHg higher and diastolic readings (the bottom number) about 2.3 mmHg higher on average.
Why Forearm Readings Run Higher
Blood pressure naturally varies depending on where you measure it. As blood travels from the upper arm toward the hand, the arteries narrow and the pressure wave changes shape, which tends to amplify the reading. In a study comparing the two sites, researchers found the forearm consistently produced higher numbers, with the difference being statistically significant for both systolic and diastolic values.
This matters most when you’re close to a diagnostic cutoff. If your forearm reading is 134/88 and the site adds roughly 4/2 mmHg, your actual upper arm pressure might be closer to 130/86. That gap could be the difference between a normal reading and a hypertension diagnosis at the 130/80 threshold.
How Accurate Is It for Detecting Hypertension?
A diagnostic accuracy review published in BMJ Open found that forearm blood pressure measurement, when held at heart level, had a sensitivity of 84% and a specificity of 75% for diagnosing hypertension compared to a properly fitted upper arm cuff. In practical terms, that means forearm readings correctly identify about 84 out of 100 people who actually have high blood pressure, but roughly 25 out of 100 people without hypertension would get a falsely elevated result.
For comparison, the American Heart Association notes that wrist measurements actually perform better than forearm readings in terms of sensitivity and specificity for hypertension screening. So if the upper arm isn’t an option, a validated wrist monitor may be a more reliable alternative than wrapping a standard cuff around your forearm.
When Forearm Measurement Makes Sense
The most common reason people need a forearm reading is that standard blood pressure cuffs don’t fit their upper arm. This is especially relevant for people with obesity, where the upper arm may be too large or too cone-shaped for even a large adult cuff to sit properly. An ill-fitting cuff on the upper arm can produce readings that are just as inaccurate as a forearm measurement, so the forearm becomes a reasonable fallback.
A study of 129 obese patients (average BMI of 40) confirmed that forearm readings with a standard cuff consistently overestimated blood pressure compared to upper arm readings taken with a correctly sized cuff. The researchers developed correction equations to adjust forearm values for patients with arm circumferences between 32 and 44 cm, which suggests that with the right math, forearm readings can still be clinically useful.
Other situations where the upper arm may be off-limits include IV lines in both arms, injuries, burns, or recent surgery on the upper arms.
When to Avoid Forearm Measurement
The same conditions that prevent upper arm measurement on a given limb also apply to the forearm on that limb. Avoid placing a cuff on any arm (upper or lower) that has:
- A dialysis shunt or fistula: the pressure from the cuff can damage the access site
- Recent surgical wounds: compression could disrupt healing or cause pain
- Lymphedema: cuff inflation may worsen swelling or cause discomfort
- IV lines or venous catheters: the cuff can interfere with fluid delivery or dislodge the line
- Prior mastectomy on that side: blood pressure measurement on the affected arm is generally avoided due to lymphatic concerns
How to Get the Best Forearm Reading
If you’re using a standard blood pressure cuff on the forearm, position matters more than it does on the upper arm because the forearm sits farther from the heart when your arm hangs naturally. Every inch below heart level inflates the reading further.
Sit with your forearm resting on a table or desk so the cuff is level with your heart. The middle of your chest at the nipple line is a good reference point. Wrap the cuff snugly around the widest part of your forearm, typically a few inches below the elbow, with the artery marker (if your cuff has one) aligned over the inside of your forearm where you’d feel your pulse.
Take at least two readings, one to two minutes apart, and average them. Keep your legs uncrossed, your back supported, and stay still and quiet during measurement. These basics apply to any blood pressure reading, but they’re especially important on the forearm where small positioning errors have a bigger impact on accuracy.
Should You Track Forearm Readings Over Time?
If you consistently measure on the forearm because the upper arm isn’t an option for you, the readings can still be valuable for tracking trends. A forearm reading that goes from 138 to 155 over several months signals a meaningful change, even if the absolute numbers don’t perfectly match what an upper arm cuff would show. The key is consistency: always use the same arm, same position, same cuff, and same time of day.
Let your doctor know you’re measuring on the forearm so they can interpret the numbers in context. Some clinicians will apply a manual correction, subtracting a few points from the systolic and diastolic values, while others may want to confirm with an in-office measurement using a properly sized upper arm cuff before making treatment decisions.