Harr Hematology Practice Test

The diagnosis of multiple myeloma is characterized by several hallmark findings that are critical for its identification. The presence of marrow plasmacytosis, which refers to the increased number of plasma cells in the bone marrow, is a defining feature of the disease. Similarly, lytic bone lesions are also commonly observed as multiple myeloma leads to the destruction of bone tissue.

Moreover, the identification of a serum and/or urine M component or monoclonal protein is a significant diagnostic criterion. Elevated levels of these proteins are indicative of the proliferation of abnormal plasma cells, a fundamental aspect of multiple myeloma.

In contrast, the Philadelphia chromosome is specifically associated with chronic myeloid leukemia, not multiple myeloma. The presence of this particular genetic abnormality does not fit within the diagnostic framework of multiple myeloma, thus confirming that it is the correct exception in this context.