BM EXAM

• In adults, bone marrow accounts for 3.4% to 5.9% of body weight, contributes 1600 to 3700 g or a volume of 30 to 50 mL/kg, and produces roughly 6 billion blood cells per kilogram per day in a process called hematopoiesis
• At birth, nearly all bones contain red hematopoietic marrow. In the fifth to seventh year of life, adipocytes (fat cells) begin to replace red marrow in the long bones of the hands, feet, legs, and arms, producing yellow marrow, and by late adolescence hematopoietic marrow is limited to the lower skull, vertebrae, shoulder, pelvic girdle, ribs, and sternum
• Yellow marrow retains the ability to revert to active hematopoiesis by increasing red marrow volume, in conditions such as chronic blood loss or hemolytic anemia when there is increased demand
• Arrangement of red marrow and its relationship to the central venous sinus

  • Hematopoietic tissue is enmeshed in spongy trabeculae (bony tissue) surrounding a network of sinuses that originate at the endosteum (vascular layer just within the bone) and terminate in collecting venules
  • Adipocytes occupy approximately 50% of red hematopoietic marrow space in a 30- to 70-year-old adult, and fatty metamorphosis increases approximately 10% per decade after age 70
• With improvements in flow cytometry phenotyping and increasing availability of 10-color laser instrumentation, immunohistochemistry, cytogenetic studies, and molecular diagnostics such as circulating tumor cell analysis, peripheral blood may often provide information historically available only from bone marrow, reducing the demand for marrow specimens
• These advanced techniques also augment bone marrow-based diagnosis and thus potentially raise the demand for bone marrow examinations in assessment of conditions not previously diagnosed through bone marrow examination
• Indications for bone marrow examination

  • Neoplasia diagnosis
  • Neoplasia diagnosis and staging
  • Marrow failure: cytopenias
  • Metabolic disorders
  • Infections
  • Monitoring of treatment
• Bone marrow puncture is prohibited in patients with coagulopathies such as hemophilia or vitamin K deficiency, although thrombocytopenia (low platelet count) is not an absolute contraindication
• Special precautions such as bridging therapy may be necessary to prevent uncontrolled bleeding when a bone marrow procedure is performed on a patient receiving anticoagulant therapy, such as Coumadin or heparin
• Bone marrow specimen collection

  • Consists of an aspirate (obtained by bone marrow aspiration) and a core biopsy specimen (obtained by trephine biopsy), both examined with light microscopy using varying magnification
  • The aspirate is examined to identify the types and proportions of hematologic cells and to look for morphologic variance
  • The core biopsy specimen demonstrates bone marrow architecture: the spatial relationship of hematologic cells to fat, connective tissue, and bony stroma, and is used to estimate cellularity
• The core biopsy specimen is particularly important for evaluating diseases that characteristically produce focal lesions, rather than diffuse involvement of the marrow
• Granulomas


  • Cell accumulations that contain Langerhans cells-large, activated granular macrophages that look like epithelial cells
  • Signal chronic infection
• Bone marrow collection sites

  • Posterior superior iliac crest of the pelvis
  • Anterior superior iliac crest of the pelvis
  • Sternum, below the angle of Lewis at the second intercostal space
  • Anterior medial surface of the tibia in children younger than age 2
  • Spinous process of the vertebrae, ribs, or other red marrow-containing bones
• Adverse outcomes occur in less than 0.05% of marrow collections. Infections and reactions to anesthetics may occur, but the most common side effect is hemorrhage associated with platelet function disorder or thrombocytopenia
• Bone marrow aspiration and biopsy procedure

  1. Preparation

  2. Core biopsy procedure

  3. Aspiration procedure
• Bone Marrow Biopsy Procedure

  1. Palpate posterior, superior iliac crest

  2. Infiltrate skin, dermis, and subcutaneous tissue with local anesthetic

  3. Insert 25-gauge needle to produce 0.5-1.0 cm papule

  4. Replace 25-gauge needle with 21-gauge needle and insert through papule to periosteum

  5. Inject 2 mL of anesthetic over dime-sized area while rotating needle

  6. Withdraw anesthesia needle

  7. Make 3-mm skin incision over puncture site with no. 11 scalpel blade
• Core Biopsy Procedure


  1. Insert Jamshidi outer cannula with obturator through skin and cortex of bone

  2. Remove obturator

  3. Insert biopsy needle through cannula and slowly advance 2-3 cm with continuous reciprocating rotation

  4. Change needle angle slightly to separate core cylinder from marrow cavity

  5. Withdraw biopsy needle and cannula, taking core cylinder

  6. Place core cylinder on slide and prepare imprints

  7. Transfer core cylinder to fixative
• Westerman-Jensen Needle Biopsy Technique

  1. Puncture through bone cortex with needle and obturator in place

  2. Remove obturator, insert cutting blades through cannula

  3. Advance cutting blades into medullary cavity

  4. Press cutting blades into medullary bone, hold cannula stationary

  5. Slowly withdraw blades to entrap tissue in cannula

  6. Withdraw entire unit, extrude specimen through hub of needle
• Aspiration Procedure


  1. Insert 14-18 gauge aspiration needle with obturator through skin and cortex of bone

  2. Remove obturator, attach 10-20 mL syringe

  3. Withdraw plunger to create negative pressure and aspirate 1.0-1.5 mL of marrow

  4. Detach syringe and pass to lab professional to expel onto slides

  5. Physician may attach second syringe to aspirate additional specimen
• If no marrow is obtained, the physician returns the obturator, advances the needle, attaches a fresh syringe, and tries again
• If the marrow is fibrotic, acellular, or packed with leukemic cells, the first and second aspiration may be unsuccessful, known as a dry tap
• In the case of a dry tap, a core biopsy is necessary to confirm whether this is indeed a dry tap
• Dry tap


  Fibrotic, packed marrow (or empty marrow in cases of very low cellularity)
• Patient Care


  Physician applies pressure dressing and advises patient to remain in same position for 60 minutes to prevent bleeding
• Direct Aspirate Smears


  1. Lab professional receives aspirate syringe, transfers drops to slides, spreads into wedge-shaped smears

  2. Lightly fans smears to promote rapid drying
• Bony spicules and fat globules

  Indicate a specimen with more cells to identify and categorize
• Anticoagulated Aspirate Smears


  Lab professional expresses aspirate into EDTA vial, pipettes to slides, spreads using same approach as direct smears
• Crush Smears of Bone Marrow Aspirate

  1. Lab professional expels aspirate to Petri dish/watch glass with EDTA, transfers spicules to slides, crushes with second slide

  2. May add albumin to EDTA solution
• Concentrate (Buffy Coat) Smears

  1. Lab professional transfers 1.5 mL EDTA-anticoagulated aspirate to tube, centrifuges, examines 4 layers

  2. Aspirates portion of myeloid-erythroid layer with plasma, transfers to Petri dish/watch glass, prepares smears using crush technique
• Core Biopsy Imprints (Touch Preparations)


  Lab professional touches core biopsy specimen to washed glass slide/coverslip to attach cells
• Histologic Sections (Cell Block) of the Core Biopsy

  Remaining core biopsy specimen suspended in 10% formalin, Zenker glacial acetic, or other fixative for histology preparation
• Crush smear preparation using coverslips may yield better morphologic information than glass slides
• Buffy coat smears compensate for hypocellular marrow and allow examination of large numbers of nucleated cells, but cell distribution is distorted
• Core biopsy imprints can closely replicate aspirate morphology, although few spicules are transferred
• Core Biopsy Imprints (Touch Preparations)

  1. Core biopsy specimens and clotted marrow may be held in forceps and repeatedly touched to a washed glass slide or coverslip so that cells attach and rapidly dry

  2. When touching the specimen to the glass slide, the medical laboratory professional lifts directly upward to prevent cell distortion
• Imprints


  • Valuable when the specimen has clotted or there is a dry tap (no specimen collected with the aspiration technique)
  • The cell morphology may closely replicate aspirate morphology, although few spicules are transferred
• Histologic Sections (Cell Block) of the Core Biopsy

  1. The remaining core biopsy specimen, spicules, or clotted specimen is submitted to histology for preparation

  2. The specimen is suspended in 10% formalin, Zenker glacial acetic acid, or B5 fixative for approximately 2 hours

  3. The fixed specimen is subsequently centrifuged, and the pellet is decalcified and wrapped in an embedding bag or lens paper and placed in a paraffin-embedding cassette

  4. A histotechnologist sections the embedded specimen, applies hematoxylin and eosin (H&E) stain, and examines the section
• Marrow aspirate smears


  • Stained with Wright or Wright-Giemsa stains using the same protocols as for peripheral blood film staining
  • Some laboratory personnel prefer to increase staining time to compensate for the relative thickness of marrow smears compared with peripheral blood films
• Marrow aspirate smears and core biopsy specimens

  • May be stained using an acidic potassium ferrocyanide (Prussian blue) solution to detect and estimate marrow storage iron or iron metabolism abnormalities
  • A number of cytochemical stains may be used for cell identification or differentiation
• Cytochemical Stains Used to Identify Bone Marrow Cells and Maturation Stages


  • Myeloperoxidase (MPO)
  • Sudan black B (SBB)
  • Periodic acid-Schiff (PAS)
  • Esterases
  • Tartrate-resistant acid phosphatase (TRAP)