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Introduction ⬇

Basophils, which constitute a small percentage of the total leukocyte count, are considered phagocytic. The basophilic granules contain heparin, histamines, and serotonin. Tissue basophils are called mast cells and are similar to blood basophils. Normally, mast cells are not found in peripheral blood and are rarely seen in healthy bone marrow.

Basophil counts are used to study chronic inflammation. There is a positive correlation between high basophil counts and high concentrations of blood histamines, although this correlation does not imply cause and effect. It is extremely difficult to diagnose basopenia because a 1000–10,000 count differential would have to be done to get an absolute count.

Normal Findings ⬆ ⬇

Absolute count: 15–50/mm3 or 0.02–0.05 × 109/L

Differential: 0%–1.0% of total WBC count

Procedure ⬆ ⬇

  1. Obtain a 5-mL venous whole blood sample in a lavender-topped tube (with EDTA) and label the specimen with the patient’s name, date and time of collection, and test(s) ordered.

  2. Count as part of the differential.

Clinical Implications ⬆ ⬇

  1. Basophilia (increased count) >50/mm3 or >0.05 × 109/L is commonly associated with the following:

    1. Granulocytic (myelocytic) leukemia

    2. Acute basophilic leukemia

    3. Myeloid metaplasia, myeloproliferative disorders

    4. Hodgkin disease

  2. It is less commonly associated with the following:

    1. Inflammation, allergy, or sinusitis

    2. Polycythemia vera

    3. Chronic hemolytic anemia

    4. After splenectomy

    5. After ionizing radiation

    6. Hypothyroidism

    7. Infections, including tuberculosis, smallpox, chickenpox, influenza

    8. Foreign protein injection

  3. Basopenia (decreased count) <20/mm3 or <0.02 × 109/L is associated with the following:

    1. Acute phase of infection

    2. Hyperthyroidism

    3. Stress reactions (e.g., pregnancy, MI)

    4. After prolonged steroid therapy, chemotherapy, radiation

    5. Hereditary absence of basophils

    6. Acute rheumatic fever in children

  4. Presence of numbers of tissue mast cells (tissue basophils) is associated with the following:

    1. RA

    2. Urticaria, asthma

    3. Anaphylactic shock

    4. Hypoadrenalism

    5. Lymphoma

    6. Macroglobulinemia

    7. Mast cell leukemia

    8. Lymphoma invading bone marrow

    9. Urticaria pigmentosa

    10. Asthma

    11. Chronic liver or renal disease

    12. Osteoporosis

    13. Systemic mastocytosis

Interventions ⬆ ⬇

Pretest Patient Care

  1. Explain test purpose and procedure.

  2. Refer to standard patient care for CBC and differential count. Also, follow guidelines in Chapter 1 for safe, effective, informed pretest care.

Posttest Patient Care

  1. Review test results; report and record findings. Modify the nursing care plan as needed. Counsel the patient regarding abnormal findings; explain the need for possible follow-up testing and treatment.

  2. Use special precautions if patient is receiving steroid therapy, epinephrine, thyroxine, or prostaglandins. Eosinophilia can be masked by steroid use.

  3. Refer to standard posttest care for hemogram, CBC, and differential count. Also, follow guidelines in Chapter 1 for safe, effective, informed posttest care.

Interfering Factors ⬆

see Appendix E for drugs that affect test outcomes.