Relationship between blood counts during follow-up and risk of thrombosis. The curve of best fit is shown as a thick green line with the 95% confidence intervals for the curve shown as thin green lines. A hazard ratio of 1 (dashed line) indicates no increased risk of thrombosis, whereas > 1 indicates increased risk. Counts at which events occurred are marked with an orange line above the x axis; counts at which no events occurred are marked with black ticks. Curves are shown for platelet count (A), WBC count (B), and Hb concentration (C).