前陣子剛好有研究。
現在血壓計大多都很準了，
不過重點是臂環的尺寸是否正確。
手臂太粗或是太細的要注意一下。
像我媽手臂只有 19 cm，
用一般尺寸的就會量不準。

可以參考英國高血壓協會的認證清單

http://www.bhsoc.org/bp_monitors/automatic.stm

All the monitors listed on this website have been clinically validated. This means that all the machines, regardless of their cost, give reliable readings when used correctly.
...
This is important because a cuff that is too large or too small will give an inaccurate reading.

我最後是買 Microlife ，之前有得到台灣精品獎，
打電話給總公司問小號的臂環，小姐說可以再送我一個小臂環，
服務、品質、價格我都很滿意，
臂環的收納設計也很方便。