Very low risk group (0 points), low risk group (1 point), intermediate risk group (2 points), high risk group (3-4 points), very high risk group (5-6 points).

Dependence on red blood cell transfusion and iron overload not only cause organ damage but can also directly impair the hematopoietic system, potentially affecting the natural course of MDS patients. Therefore, WPSS was developed, including WHO classification, IPSS cytogenetic grouping, and red blood cell transfusion dependence. WPSS, as a time-continuous evaluation system, can be used to assess prognosis at any stage of a patient's life.

*Due to the difficulty in standardizing transfusion criteria, it was found that hemoglobin levels below 90g/L in men and below 80g/L in women significantly affect prognosis. Therefore, WPSS was revised in 2011, with subgroup scores remaining unchanged.