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Sokal Index for Chronic Myelogenous Leukemia (CML)

Relative-risk prognostic index for chronic-phase CML at diagnosis.

Sokal Index for Chronic Myelogenous Leukemia (CML)
Age
years
Spleen size below costal margin
cm
Platelet count
x10⁹/L
Peripheral blood blasts
%
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When to use

  • Baseline prognostic risk stratification of newly diagnosed chronic-phase CML.

Formula

Relative risk = exp[0.0116 x (age - 43.4) + 0.0345 x (spleen size cm - 7.51) + 0.188 x ((platelets/700)^2 - 0.563) + 0.0887 x (blast% - 2.10)]. Low risk <0.8, intermediate 0.8-1.2, high >1.2.

Pearls and pitfalls

  • Developed in the pre-tyrosine-kinase-inhibitor era but remains widely used for baseline risk stratification alongside the Hasford/EUTOS scores.

References

  1. Sokal JE, et al. Blood. 1984;63(4):789-799.