Biopsy, Bone Marrow

General

Synonym/Acronym:
N/A

Rationale
To assist in diagnosing hematological diseases and in identifying and staging myeloproliferative tumors and leukemias.

Patient Preparation
There are no food, fluid, activity, or medication restrictions unless by medical direction. However, to reduce the risk of aspiration related to nausea or vomiting, the patient may be requested to abstain from solid food and milk or milk products for at least 6 hr, and clear liquids are restricted for at least 2 hr prior to general anesthesia, regional anesthesia, or sedation/analgesia (monitored anesthesia). The patient may be required to be NPO at midnight. The American Society of Anesthesiologists has fasting guidelines for risk levels according to patient status. More information can be located at www.asahq.org.

Regarding the patient’s risk for bleeding, the patient should be instructed to avoid taking natural products and medications with known anticoagulant, antiplatelet, or thrombolytic properties or to reduce dosage, as ordered, prior to the procedure. Number of days to withhold medication is dependent on the type of anticoagulant. Note the last time and dose of medication taken. Protocols may vary among facilities.

Normal Findings
(Method: Microscopic study of bone and bone marrow samples, flow cytometry) Reference ranges are subject to many variables, and therefore the laboratory should be consulted for their specific interpretation. Some generalities may be commented on regarding findings as follows:

  • Ratio of marrow fat to cellular elements is related to age, with the amount of fat increasing with increasing age.
  • Normal cellularity, cellular distribution, presence of megakaryocytes, and absence of fibrosis or tumor cells.
  • The myeloid-to-erythrocyte ratio (M:E) is 2:1 to 4:1 in adults. It may be slightly higher in children.
Differential ParameterConventional Units
Erythrocyte precursors18%–32%
Myeloblasts0%–2%
Promyelocytes2%–6%
Myelocytes9%–17%
Metamyelocytes7%–25%
Bands10%–16%
Neutrophils18%–28%
Eosinophils and precursors1%–5%
Basophils and precursors0%–1%
Monocytes and precursors1%–5%
Lymphocytes9%–19%
Plasma cells0%–1%

Critical Findings and Potential Interventions

  • Classification or grading of tumor
  • Identification of malignancy

Timely notification to the requesting health-care provider (HCP) of any critical findings and related symptoms is a role expectation of the professional nurse. A listing of these findings varies among facilities.

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