Figure 2.

(A) Platelet count of children and adults at the time of ITP diagnosis. The vertical line indicates a platelet count of 20x10⁹/L. (B) Platelet counts of children and adults at the time of the diagnosis of ITP are plotted as quantile-quantile plot to compare the distribution of platelet counts of children and adults. A logarithmic scale was chosen in order to highlight platelets <50x10⁹/L. With equal size of the number of observations (N) for children and adults, each data set is ranked from the smallest to the highest value. This gives N pairs (x,y) from (x_min/y_min) to (x_max/y_max) and each pair is a point in the quantile-quantile plot. If the two distributions are similar, the points occur approximately on the diagonal of the plot. For unequal size of the two data sets interpolation to the same quantile is used.