Whilst very low-count MBL rarely progresses to CLL, high-count MBL progresses to CLL requiring therapy at a level of 1% to 2% per year. Large-rely MBL is distinguished from Rai 0 CLL according to whether the B-cell depend is higher than or under 5 × 109/L. While individuals with equally higher-depend MBL and CLL Rai stage 0 are at elevated hazard