VCP 411: Medicine Section

ASPIRATION Vs CORE

• An aspirate of bone marrow provides a few drops of marrow-blood mixture that is placed on a glass slide and evaluated as cytology. A core of bone marrow is a 3D piece of marrow tissue on which histology is performed to provide information about the marrow elements in relationship to the supporting stroma of the marrow. In most circumstances an aspirate is obtained first and often provides sufficient information such that a core sample is not needed. The primary indication for a core sample is procurement of an aspiration sample that is low in cellularity. A core can be obtained to determine to if the low cellularity is due to poor sampling technique or if the marrow truly is hypocellular. Before placing the core of bone marrow tissue into formalin, roll the sample on a glass slide for a cytologic impression, while awaiting the results of the core biopsy.
• The sites that are most accessible for bone marrow aspiration in the dog are the proximal humerus, proximal femur and the wing of the ilium, approached either from the dorsal crest or lateral face. The easiest sites from which to obtain bone marrow in the cat are the proximal femur and proximal humerus. Core samples are most often obtained from the proximal humerus, or proximal femur.
• Both the proximal humerus and proximal femur are easily accessible in most cats.