One of the most important factors that can influence the accuracy of blood pressure readings is the size of the blood pressure cuff that is used. While a very specific set of guidelines regarding precise cuff sizing is in place, it can be difficult for patients to tell, just by looking, if their healthcare provider is using a correctly sized cuff.
If you are significantly above or below "average" height or weight, then the doctor or nurse should probably not be using the cuff that is already in the room. The "default" cuff that is usually kept in the examining room is meant to be used for average sized people, and will not produce an accurate reading if you are larger or smaller than average.
The official guidelines specify the following cuff sizes:
- Arm circumference 22 to 26 cm, 'small adult' cuff, 12 x 22 cm
- Arm circumference 27 to 34 cm, 'adult' cuff: 16 x 30 cm
- Arm circumference 35 to 44 cm, 'large adult' cuff: 16 x 36 cm
- Arm circumference 45 to 52 cm, 'adult thigh' cuff; 16 x 42