The importance of flowcytometry study with the first aspirate taken during bone marrow aspiration in the diagnosis of multiple myeloma and follow-up of minimal residual disease

Objective: Flow cytometry (FC) is a diagnostic method supporting traditional morphological examination in disease follow-up and the diagnosis of Multiple myeloma (MM). Normal and atypical plasma cells (PCs) can be told apart from each other by means of FC method. The plasma cell rate is the highest in the blood obtained in the first aspirate during bone marrow aspiration in MM. Material and methods: A total of 60 patients that have been diagnosed with MM between 2018 and 2020, including 30 patients whom flow cytometry was studied with the first aspirate during bone marrow aspiration, and 30 patients whom FC was studied with the second aspirate were included in our study. The characteristics of the patients were analyzed retrospectively from their files. Results: The median ratio of plasma cells (PCs) detected by FC and bone marrow biopsy  was 17,5% and 44%, respectively. While this rate was median 37,5% in patients that flow cytometric study was performed with the first aspirate, the rate was found to be median 7% in patients that FC was performed with the second sample. The PCs rates were statistically significantly higher with the flow cytometric study with the first aspirate than the second one (p=0.000). Conclusion: Flow cytometric study with the first aspirate during bone marrow aspiration in patients with MM is diagnostically important.