Certified Medical Assistant (CMA AAMA)Clinical Workflow and Patient IntakeMedium
A medical assistant is preparing to take a blood pressure reading and selects a cuff that is too small for the patient's arm circumference. What effect will this have on the reading?
- AThe reading will be falsely low
- BThe reading will be falsely high
- CThe reading will be unaffected
- DOnly the diastolic value will be affected
Show answer & explanationAnswer & explanation
Correct answer: B. The reading will be falsely high
A cuff that is too small requires more pressure to occlude the brachial artery, producing a falsely elevated blood pressure reading. Cuff width should be about 40% of the arm's circumference for accuracy.
Why the other options are wrong
- A. Incorrect; too-small cuffs overestimate, not underestimate, pressure.
- C. Incorrect; cuff size significantly affects accuracy.
- D. Incorrect; both systolic and diastolic readings can be falsely elevated.
Blood Pressure Cuff Sizing
Using an incorrectly sized BP cuff causes measurement error: too small overestimates, too large underestimates blood pressure.
- Cuff bladder width should be ~40% of arm circumference
- Too small cuff = falsely high reading
- Too large cuff = falsely low reading
Memory trick: Small cuff, big number