Standard risk group (SR)

High Risk group (HR)

(All the criteria below should exist)

(One of the criterion below is adequate)

Age at diagnose ≥ 1 year or < 6 year

Intermediate risk group and blast count in bone marrow at day 15% ≥ 25%

Leukocyte count at the beginning < 20.000/mm³

Blast count in peripheral blood at day 8 > 1000/mm³

Blast count in peripheral blood at day 8 < 1000/mm³

Blast count in bone marrow at day 15% ≥ 5%

Blast count in bone marrow at day 15% < 25%

t (9; 22) [BCR/ABL] or t (4; 11) [MLL/AF4] positivity

Blast count in bone marrow at day 15% < 5%

Hipodiploidy ≤ 45

Intermediate risk group (IR): Patients not fully complying with the criteria of standard or high risk groups