Kaplan-Meier survival curves for 104 patients with CLL, including 68 CLLs with low Rai stage. (A) OS for patients with CLL was classified into 3 levels according to the 21FK score (0/2, 1/2, and 2/2). (B) OS for patients with CLL was classified into 3 levels according to the 181bFK score (0/2, 1/2, and 2/2). (C) Among the 104 patients, the 21FK score was validated in 68 patients with low Rai stage CLL. The 21FK score predicted patients' survival, even if they had a Rai disease stage of 0, 1, or 2. The survival data were compared, and the reported P values were calculated according to the log-rank test. In the main text, the P values were reported according to Cox regression analyses associated with the hazard ratio computation.