VCP 411: Medicine Section

TECHNIQUE

•  Dogs will often tolerate procurement of a marrow aspirate using only local anesthesia whereas heavy sedation or general anesthesia is required to collect a core sample. General anesthesia is required for either aspiration or core in the cat. The area for bone puncture should be aseptically prepared and sterile.
• A 12 or 20 ml syringe is used to aspirate bone marrow. It may be necessary to pull ck on the syringe plunger to 10-15 ml to create enough negative pressure to break marrow particles loose from the endosteal surface. Aspirate only a small amount of marrow. Aspiration of large volumes results in dilution of the marrow sample with peripheral blood from the venous sinuses in the marrow cavity. When marrow just enters the barrel of the syringe, stop aspirating. Larger volumes of marrow can be drawn into an EDTA solution and the marrow particles (spicules) picked out with a needle or pipette. Bone marrow clots very fast so the slides should be close at hand so the sample can be placed on the slides immediately after collection.