The bone marrow is a soft pulpy tissue found inside some bones in the body. The bone marrow contains cells that ultimately develop into the different types of blood cells - red cells, white cells and platelets.
Doctors test the bone marrow by removing a small amount of it and seeing it under the microscope. There are two types of bone marrow tests â bone marrow aspiration and bone marrow biopsy. In aspiration, a thin needle is used to simply suck out some cells from the marrow. In a bone marrow biopsy a small tissue piece is removed intact from the marrow using a thicker needle.
