E) Bone marrow biopsy
Bone marrow biopsy is an investigation commonly requested for patients presenting with symptoms of decreased blood cells or showing pancytopenia on complete blood count test. The procedure is usually done in an outpatient setting in clinics and in some cases in hospitals. A specimen of the bone marrow commonly taken from the hip bone is obtained using a special needle and examined under the microscope. In case of multiple myeloma, the specimen will show an excessive plasma cell count.