Shalabi H, Yuan CM, Kulshreshtha A, et al. - Researchers performed a retrospective comparison between bone marrow (BM) biopsy, aspirate, and flow cytometry (FC) samples obtained from children and young adults with relapsed/refractory acute lymphoblastic leukemia (ALL) in order to recognize the frequency and degree of disease discrepancies in this population. Also, the central nervous system FC was compared with cytopathology techniques. Discrepant results were evident in 60 of 410 (14.6%) BM samples; of these, 41 (10%) were clinically relevant as they led to a change in the assignment of marrow status. Twenty-eight of 89 (31.5%) evaluated patients exhibited discrepant BM results. Additionally, the disease was identified in 9.7% of cases via cerebrospinal fluid (CSF) FC where cytopathology was negative. In view of these findings, further investigation of the role of concurrent BM biopsy, with aspirate and FC evaluations, and the addition of FC to CSF evaluations are recommended for completely evaluating disease status and response, especially in cases with relapsed/refractory ALL.