Bone marrow aspirate and biopsy

Bone marrow aspirate and bone marrow biopsy are two examinations used in the evaluation of the bone marrow, indicated in case of unexplained haemotological disorder (like unexplained anaemia, leukopaenia, etc.) and in the evaluation of leukaemia and lymphoma.

Bone marrow aspiration involves aspirating a small part of the liquid bone marrow. This is technically more simple to perform and gives information on the number and features of the cells (cytological information) of the bone marrow. Bone marrow biopsy involves removing a solid piece of bone marrow, giving histological information. This is more technically difficult and more expensive to perform, and bone marrow biopsies require 2-3 days of processing before it can be examined.

Aspiration and biopsy both give complementary information and they are therefore usually performed together. Some conditions are better evaluated with aspiration and some are better evaluated with biopsy. They can be performed in the same setting.

Interpretation

When distinguishing acute from chronic haematological disorders of the bone marrow, one must determine the percentage of WBCs in the bone marrow which are blasts (immature). If > 20% of bone marrow cells are blasts, the disorder is acute (for example acute leukaemia).