The extent of inaccurate aneroid sphygmomanometers in a hospital setting.

All 832 hospital hand-held aneroid sphygmomanometers without exception were examined for their accuracy within a +/- 3 mmHg margin by comparing them to a certified mercury device. Of these, 59.9% were inaccurate, with the majority giving lower readings than noted on the mercury scale. The findings are unsatisfactory and correspond to earlier reports whose study designs and interpretations of permissible limits varied widely. The instruments daily wear and tear is compounded by damage incurred by dropping and/or jolting, which could render the device inaccurate. Although it is generally recommended that aneroid manometers be inspected every six months, this seems not to be adequate.