Figure 3

Error grid analysis, redrawn after [15] using a linear regression plot between SpHb and Hb values (g/dl). The dotted lines indicate the 95% prediction bands, in which 95% of the data points are expected to fall. The graph is consisting of three zones (red, yellow, green), in which the bias of the measurements results in different clinical decisions. While in the green zone the bias is without further therapeutic consequence, the errors lying in the yellow or red zone may lead to major therapeutic errors.