Bone marrow examination (aspiration, biopsy) requires removal of a small sample of bone marrow by aspiration, needle biopsy, or open surgical biopsy. Cells normally present in hematopoietic marrow include erythrocytes and granulocytes (neutrophils, basophils, and eosinophils) in all stages of maturation; megakaryocytes (from which platelets develop); small numbers of lymphocytes; and occasional plasma cells (Fig. 1-2). Nucleated WBCs in the bone marrow normally outnumber nucleated (immature) RBCs by about 3:1. This is called the myeloid-to-erythroid (M:E) ratio.⁸ Causes of increased and decreased values on bone marrow examination are presented in Table 1-3.

Various stains followed by microscopic examination can be performed on bone marrow aspirate to diagnose and differentiate among the different types of leukemia. A Sudan B stain differentiates between acute granulocytic and lymphocytic leukemia. A periodic acid-Schiff stain assists in the diagnosis of acute lymphocytic leukemia and erythroleukemia. A terminal deoxynucleotidyl transferase test differentiates between lymphoblastic leukemia and lymphoma.⁹

Because bone marrow examination involves an invasive procedure with risks of infection, trauma, and bleeding, a signed consent is required.

Note: There may be differences in normal values among individuals and in values obtained by different laboratory techniques.

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Indications

• Evaluation of abnormal results of CBC (e.g., anemia), of WBC count with differential (e.g., increased numbers of leukocyte precursors), or of both tests
• Monitoring of effects of exposure to bone marrow depressants
• Monitoring of bone marrow response to antineoplastic or radiation therapy for malignancies
• Evaluation of hepatomegaly (enlarged liver) or splenomegaly (enlarged spleen)
• Identification of bone marrow hyperplasia or hypoplasia, although the study may not indicate the cause of the quantitative abnormality
• Determination of marrow differential (proportion of the various types of cells present in the marrow) and M:E ratio
• Diagnosis of various disorders associated with abnormal hematopoiesis:
  • Multiple myeloma
  • Most leukemias, both acute and chronic
  • Disseminated infections (granulomatous, bacterial, fungal)
  • Lipid or glycogen storage diseases
  • Hypoplastic anemia (which may be caused by chronic infection, hypothyroidism, chronic renal failure, advanced liver disease, and a number of "idiopathic" conditions)
  • Erythropoietic hyperplasia (which may be caused by iron deficiency, thalassemias, hemoglobinopathies, disorders of folate and vitamin B₁₂ metabolism, hypersplenism, glucose-6-phosphate dehydrogenase [G-6-PD] deficiency, hereditary spherocytosis, and antibody-mediated bacterial or chemical hemolysis)
  • Lupus erythematosus
  • Porphyria erythropoietica
  • Parasitic infestations
  • Amyloidosis
  • Polycythemia vera
  • Aplastic anemia (which may be caused by drug toxicity, idiopathic marrow failure, or infection)

Contraindications

• Known coagulation defects, although the test may be performed if the importance of the information to be obtained outweighs the risks involved in carrying out the test

[Section Outline]

• Indications
• Contraindications

Nursing Care Before the Procedure

Explain to the client:

• The purpose of the study
• That it will be done at the bedside by a physician and requires about 20 minutes
• The general procedure, including the sensations to be expected (momentary pain as the skin is injected with local anesthetic and again as the needle penetrates the periosteum, the "pulling" sensation as the specimen is withdrawn)
• That discomfort will be minimized with local anesthetics or systemic analgesics
• That the site may remain tender for several weeks

Ensure that a signed consent has been obtained. Then:

• Take and record vital signs.
• Provide a hospital gown if necessary to provide access to the biopsy site or to prevent soiling of the client's clothes with the solution used for skin preparation.
• Administer premedication prescribed for pain or anxiety.

The client is assisted to the desired position depending on the site to be used. In young children, the most frequently chosen site is the proximal tibia; in older children, vertebral bodies T10 to L4 are preferred. In adults, the sternum or iliac crests are the preferred sites.

The prone or side-lying position is used if the spinous processes are the sites to be used. (These sites are preferred if more than one specimen is to be obtained.) The client may also be sitting, supported by a pillow on an overbed table for a spinous process site. The side-lying position is used if the iliac crest or tibia is the site. For sternal punctures, the supine position is used.

The skin is prepared with an antiseptic solution, draped, and anesthetized, preferably with procaine, which is painless when injected. Asepsis must be meticulous to prevent systemic infection.

For aspiration, a large needle with stylet is advanced into the marrow cavity. Penetration of the periosteum is painful. The stylet is removed and a syringe is attached to the needle. An aliquot of 0.5 mL of marrow is withdrawn. At this time, the discomfort is a "pulling" sensation rather than pain. The needle is removed and pressure applied to the site. The aspirate is immediately smeared on slides and, when dry, sprayed with a fixative.

For needle biopsy, the local anesthetic is introduced deeply enough to include the periosteum. A special cutting biopsy needle is introduced through a small skin incision and bored into the marrow cavity. A core needle is introduced through the cutting needle and a plug of marrow is removed. The needles are withdrawn and the specimen placed in a preservative solution. Pressure is applied to the site for 5 to 10 minutes and a dressing applied.

Nursing Care After the Procedure

• Care and assessment after the procedure include assisting the client to lie on the biopsied side, if the iliac crest was entered, or supine, if the vertebral bodies were used, to maintain pressure on the site for 10 to 15 minutes.
• For sternal punctures, place the client in the supine position or other position of comfort.
• Provide bed rest for at least 30 minutes after the procedure.
• Assess puncture site every 10 to 15 minutes for bleeding. Apply an ice bag to the puncture site to alleviate discomfort and prevent bleeding.
• Assess for infection at the site; note any redness, swelling, or drainage.
• Administer analgesics to alleviate discomfort.