Microscopic examination of bone marrow aspirates in malignant disorders of haematopoiesis--a comparison of two slide preparation techniques.

It is mandatory to perform microscopic examinations of bone marrow aspirates during the diagnosis of many neoplastic haematopoiesis disorders. In 2008, The International Committee for Standardization in Hematology recommended the use of two types of slides for the microscopic evaluation of bone marrow: wedge-spread film and crush film slides. Because these techniques have not yet been compared, we performed such a comparison. Routine bone marrow samples from 250 patients diagnosed due to different neoplastic haematological disorders were evaluated. The major differences between the two compared techniques were identified in 13 patients with non-Hodgkin's lymphoma, seven patients with systemic mastocytosis and 11 patients with acute leukaemias or myelodysplastic syndromes or chronic myelomonocytic leukaemia. Differences were noted also in many patients with multiple myeloma, but the clinical significance of these discrepancies was rather modest. The major causes of the differences observed seemed to be the dilution of marrow with blood cells and the focal growth of many neoplastic cells. We believe that the crush technique is more advantageous compared to the wedge-spread films. Therefore, we recommend the use of crush films as the primary method for establishing a diagnosis or for making therapeutic decisions based on the microscopic examination of bone marrow.