P652: MEASURING MINIMAL RESIDUAL DISEASE BEYOND 10-4 THROUGH IGHV LEADER-BASED NEXT GENERATION SEQUENCING IMPROVES PROGNOSTIC STRATIFICATION IN CHRONIC LYMPHOCYTIC LEUKEMIA. (23rd June 2022) - Hengeveld, P.; van der Klift, M.; Kolijn, P. M.; Davi, F.; Kavelaars, F.; de Jonge, E.; Robrecht, S.; Assmann, J.; van der Straten, L.; Ritgen, M.; Westerweel, P.; Fischer, K.; et al.