Table 1.

Mean absolute error between the values reported by the reference device and test devices (n = 327) at the pressure intervals testeda

Test pressure, mmHgbMAE, mmHg (95% CI)Failing monitors, n (%)Overestimation by ≥3 mmHg, nUnderestimation by ≥3 mmHg, n
00.27 (0.23 to 0.30)0 (0)00
500.59 (0.54 to 0.65)3 (1)12
1000.78 (0.70 to 0.86)6 (2)42
1500.98 (0.88 to 1.09)23 (7)212
2001.14 (1.01 to 1.27)30 (9)282
2501.34 (1.18 to 1.49)41 (13)356
Maximum1.46 (1.29 to 1.63)43 (13)376
  • a Four monitors could not be tested fully but should be counted as failures.

  • b Pressure is checked in 50 mmHg increments up to either 280 mmHg or 300 mmHg (according to manufacturer’s specification, the highest pressure point monitors can be tested at is either 280 mmHg or 300 mmHg) and then down again. The data at each testing interval between 0 mmHg and 250 mmHg going up have been combined with that going down. CI = confidence interval. MAE = mean absolute error.