There are several techniques that can be utilized to obtain a bone marrow aspirate. Commonly, a sterile 20 mL syringe is used to suction out the aspirate from the aspirate needle that is inserted into the bone marrow space in the patient's posterior iliac crest. Generally, 5-10 mL of marrow is aspirated in several different syringes. A large syringe allows for rapid aspirate collection because greater vacuum pressure is formed from pulling back the syringe plunger of a larger syringe. The volume of aspirate necessary for processing will vary, depending upon the need for ancillary studies such as cytogenetics, molecular diagnostics, or flow cytometry, as well as the sample volume requirements of the testing laboratory. However, larger samples of bone marrow aspirate may lead to increased contamination with sinusoidal blood and/or dilution with peripheral blood.
One method to prevent clotting of the aspirate is to coat the inside of the syringe with sodium heparin. Lithium heparin is toxic to the aspirate cells and is not acceptable for ancillary studies. Several aspirates can be obtained in separate syringes.
