 compar bone marrow studi aspir needl biopsi site bone marrow aspir diagnosi hematolog diseas condit blood system number techniqu devis suitabl specimen marrow discomfort patient needl set describ paper equal reliabl obtain bone marrow microscop studi diagnosi compar studi bone marrow aspir simultan iliac crest sternum 26 patient differ instanc dry tap iliac site fact addit observ discomfort experienc patient sternum indic sternal area reliabl effici site obtain bone marrow observ studi patient experienc discomfort univers illinoi needl major object needl inabl bone core biopsi 