[Comparison of quantitative smears prepared from EDTA-K2 anticoagulated bone marrow fluid and traditional bedside direct smears, and the clinical value of their combined use with peripheral blood smears].

Objective: Compare the preparation effects between quantitative smears of bone marrow aspirate anticoagulated with ethylene diamine tetra-acetic acid dipotassium salt dihydrat (EDTA-K2) and traditional bedside direct smear and evaluate the clinical application value of the new dual-smear combined testing mode (combining peripheral blood smears with anticoagulated quantitative smears). Methods: A prospective study was conducted, including 180 bone marrow aspirate specimens collected from patients who underwent bone marrow puncture examinations at Zhongshan Hospital, Fudan University, between January and June 2024. Both EDTA-K2 anticoagulated quantitative smears and bedside direct smears were prepared for each specimen. Based on the different preparation methods, the specimens were divided into an anticoagulated quantitative smear group(n=180) and a bedside direct smear group(n=180), and the differences in bone marrow cell morphology examinations between the two groups were compared. Using the RAND function in Excel, random numbers were generated for the 180 anticoagulated bone marrow aspirate specimens. These random numbers were then sorted in ascending order, and the first 10 EDTA-K2 anticoagulated bone marrow samples were selected. The impact of storage duration on cell morphology was evaluated after storage periods of 0, 1, 4, 8, 12, and 24 h, respectively. Additionally, the differences in clinical diagnostic concordance rates between the new dual-smear combined testing mode (combining peripheral blood smears with anticoagulated quantitative smears) and the traditional dual-smear combined testing mode (combining peripheral blood smears with bedside direct smears) were compared. Cohen's Kappa consistency analysis was used to evaluate the diagnostic agreement between the new dual-slide combined detection model and the traditional dual-slide combined detection model. Results: The morphological quality score of the anticoagulated quantitative smear group was superior to that of the bedside direct smear group [(2.98±0.18) vs (2.58±0.80) points, P<0.001], but the bone marrow smear quality score was lower than that of the bedside direct smear group [(3.08±0.83) vs (3.54±0.76) points, P<0.001]. The proportions of hypercellular and markedly hypercellular smears, the percentage of granulocytic cells, the percentage of erythroid cells, and the total number of megakaryocytes per smear were lower in the anticoagulated quantitative smear group than in the bedside direct smear group, whereas the percentage of lymphocytes was higher. Preparing smears from anticoagulated bone marrow aspirate stored for≤4 h did not significantly affect cell morphology (the proportion of cells with morphological changes was<10% of the respective cell lineage). There were no statistically significant differences in diagnostic concordance rates between the new dual-smear combined testing mode and the traditional dual-smear combined testing mode for multiple myeloma and lymphoma [multiple myeloma: 72.8%(67/92) vs 68.5%(63/92), P=0.388; lymphoma: 72.1%(31/43) vs 69.8% (30/43), P=1.000]. Moreover, both modes demonstrated high diagnostic consistency for multiple myeloma and lymphoma (Kappa values of 0.686 and 0.718, respectively). Conclusions: The morphological quality of anticoagulated quantitative smears is superior to that of bedside direct smears, and it is recommended to prepare the smears within 4 h of bone marrow aspirate collection. The diagnostic concordance rates between the new dual-smear combined testing mode and the traditional dual-smear combined testing mode are similar, with high diagnostic consistency observed between the two modes.