Importance of microscopic marrow exam
Marrow exam is a mainstay of hematologic diagnosis. Even with the advent of specialized biochemical and molecular assays that capitalize on advances in our understanding of the cell biology of hematopoiesis, the primary diagnosis of hematologic malignancies and many nonneoplastic hematologic disorders relies upon examination of the cells in the marrow. An aspirateand biopsy of the marrow can be obtained with minimal risk and only minor discomfort and are quickly and easily processed for examination.
When we do marrow exam
We do marrow exam when the clinical history, blood cell counts, blood film, or laboratory test results suggest the possibility of a primary or secondary hematologic disorder for which morphologic analysis or special studies of the marrow would aid in the diagnosis. Leukopenia, thrombocytopenia, bicytopenia, or tricytopenia nearly always require a marrow exam for diagnosis. Non hemolytic anemia that is not readily diagnosed as iron deficiency, thalassemia, vitamin B12 deficiency, folate deficiency, or another type of anemia defined by blood cell examination and supporting laboratory tests often requires a marrow examination. Abnormal cells in the blood, such as nucleated red cells, white cell precursors, abnormal lymphocytes not explained by concurrent infection, and blast cells, usually require a marrow examination.
Why we do marrow exam
In addition to determining the cellularity and morphology of precursor cells or the presence of nonhematopoietic cells, the study provides marrow cells for immuno-phenotyping by cell flow analysis, for cytogenetic studies, and in special cases for marrow cell culture. Granulomatous and storage diseases may be uncovered in the marrow, and the marrow can be used to culture fastidious organisms such as fungi and mycobacteria. Searching for ex-tranodal spread of lymphoma (staging) is another important use of the marrow examination.