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• Bone marrow aspiration


  A procedure where a sample of bone marrow is removed and examined
• Bone marrow aspiration and biopsy


  • Essential for the diagnosis of bone marrow and malignant hematologic disorders
  • e.g. Acute and chronic leukemias, Myelodysplastic syndromes, Chronic myeloproliferative disorders, Lymphomas, Plasma cell myeloma
• Bone marrow aspiration


  1. Bone marrow smears should be prepared immediately/ASAP following aspiration

  2. EDTA samples used for smear preparation

  3. Aspirate should be expelled into a small plastic or siliconized glass dish

  4. A Pasteur pipette is used to draw up particles

  5. A minimum of six smears and two particle squash ('crush') slide preparations should be made

  6. Fixed with fresh acetone-free absolute methanol

  7. Stained with a Romanowsky stain, such as May-Grunwald Giemsa or Wright Giemsa stain
• Bone marrow biopsy


  1. Performed either before or after the aspirate

  2. For the assessment of overall marrow architecture and cellularity

  3. Provide greater sensitivity for the assessment of focal lesions and patchy infiltrates

  4. Core biopsy from adult = at least 2 cm

  5. 1cm core biopsy may contain sufficient diagnostic information

  6. Biopsy specimen shrinks by 20% after processing

  7. The larger the amount of tissue that is biopsied = the greater likelihood of a focal lesion
• Fixatives for bone marrow biopsy

  • Neutral buffered formalin - Standard fixative
  • Other fixatives: Zinc formaldehyde, B5 (mercuric chloride, sodium acetate and formalin), Acetic acid-zinc-formalin, Isotonic buffered formalin, Bouin's fixative (picric acid, acetic acid and formaldehyde), Formaldehyde and glutaraldehyde
• B5 fixative


  Good morphology, Short turnaround time (TAT), Contains mercuric chloride - causing safety and environmental concerns
• Touch imprints


  1. Should be made from the trephine biopsy prior to placing in the core tissue in fixative

  2. Important if there is a 'dry tap' on bone marrow aspiration

  3. Made by gently touching the fresh unfixed core on the slide, or the slide on the core

  4. Fixing and staining: the same as smear and squash prep
• Decalcification of bone marrow specimens


  1. A small piece of bone marrow attached to a thin hard bone is decalcified for 24-48 hours

  2. Organic acids (formic and acetic) decalcify slower than mineral acids (HCL and nitric)

  3. Over-decalcification of tissue with acids, particularly mineral acids = tissue destruction

  4. Ensure even distribution of decalcifying acid around bone sample through tissue suspension, mild agitation, gentle mixing or air bubble percolation

  5. Decalcification solutions used: EDTA, formic acid, acetic acid, picric acid, nitric acid

  6. Decalcification time varies depending on type of decalcifying agent and size of biopsy specimen

  7. Decalcification with EDTA = Better preservation of nucleic acids but slower than other acid reagents

  8. Sections should not be left in solution for a longer period of time to avoid injury or destruction of cellular detail

  9. Recommended thickness of sections = 2-3 microns

  10. Methods available for routine use = Hematoxylin and eosin, Van Gieson stains
• Decalcification results in leaching out of some storage iron from the core biopsy
• Nitric acid and hydrochloric acid diminish the acid fastness of mycobacteria resulting in false negative results
• Acid fastness is retained when decalcification is in formic acid, sodium citrate, or citric acid buffer
• Plastic embedding of bone marrow core biopsy specimens


  Gives good cytological detail, Does not require decalcification