Introduction:The evaluation of plasma cell (PC) compartment is influenced by the quality of bone marrow aspirate (BMA). Herein, we evaluated the impact of sequence of pull on quality of clinical assessment in plasma cell proliferative disorders (PCPDs).Methods: Histomorphology along with smears from first pull and second pull BMA and flow cytometric immunophenotyping (FCMI) data from second pull aspirate were evaluated for cellularity and PC%.Results: Of the 484 samples, BMA smears were adequate in 87.4% of first pull (median PC = 7%; IQR = 2-25%) and 51.2% of second pull samples (median PC = 2%; IQR = 0.5-12%; p < 0.001). Recovery of PC was least on FCMI (median PC = 0.59%; IQR = 0.14-3.07%), however, sample adequacy was met in 42.6% of samples with acquisition of ≥3 million events. Second pull smears under-reported PC % in 34% of newly diagnosed multiple myeloma (NDMM) (<10% PC) and 46% of MM on therapy (<5% PC), resulting in suboptimal assessment. Bone marrow biopsy (BMBx) was evaluated in a total of 309 cases (median PC = 10.0%; IQR 4.0-40.0%) with significantly higher numbers of BMPC% on BMBx compared with first pull smears (Mean ± 2SD: 25.9% ± 30.54 vs. 20.77% ± 20.20; p = 0.001).
Conclusion:First pull BMA smears were of superior quality but inadequate in onetenth of samples. Second pull smears underreported PC% and recovery of PC compartment was poorest on FCMI. Concurrent bone marrow biopsy and use of the first pull sample for FCMI along with acquisition of a higher number of cells on FCMI may enhance the quality of assessment in PCPDs. K E Y W O R D S bone marrow biopsy, bone marrow plasma cell percentage, first pull bone marrow aspirate, flow cytometric immunophenotyping, plasma cell proliferative disorders, second pull bone marrow aspirate 1 | INTRODUCTION Identification, accurate quantitation, and characterization of neoplastic plasma cells (PC) are essential in diagnostic, prognostic as well as therapeutic monitoring of plasma cell proliferative disorders (PCPDs). The recent revised consensus guidelines by International Myeloma Working Group (IMWG) updated the disease definition criteria of multiple myeloma (MM) which was earlier based on clonal bone marrow plasma cell (BMPC) >10% to now include biomarkers of malignancy, that is, presence of clonal BMPC ≥60%, involved to uninvolved