Type and accuracy of sphygmomanometers in primary care: a cross-sectional observational study by Christine A'Court, Richard Stevens, Sarah Sanders, Alison Ward, Richard McManus, and Carl Heneghan BJGP Volume 61(590):e598-e603 September 1, 2011 ©2011 by British Journal of General Practice

Errors in blood pressure measurements in mercury, aneroid, and digital sphygmomanometers tested at 50, 100, 150,200, and 250 mmHg. Errors in blood pressure measurements in mercury, aneroid, and digital sphygmomanometers tested at 50, 100, 150,200, and 250 mmHg. Eleven errors 11–50 mmHg are not shown for reasons of scale (five readings from one aneroid device under-reading by 30 mmHg in all tests). Christine A'Court et al. Br J Gen Pract 2011;61:e598-e603 ©2011 by British Journal of General Practice

Absolute error (mean, ignoring direction of error; bars show 95% confidence intervals for the mean) in blood pressure devices when tested at 50, 100, 150,200, and 250 mmHg. Absolute error (mean, ignoring direction of error; bars show 95% confidence intervals for the mean) in blood pressure devices when tested at 50, 100, 150,200, and 250 mmHg. Christine A'Court et al. Br J Gen Pract 2011;61:e598-e603 ©2011 by British Journal of General Practice